• Advances in Energy Research
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• 제4권4호
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• pp.325-337
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• 2016

Cerbera Odollam (sea mango) is a proven promising feedstock for the production of biodiesel due to its high oil content. Fatty acid methyl esters (FAME) were produced as the final reaction product in the transesterification reflux condensation reaction of sea mango oil and methyl acetate (MA). Potassium methoxide was used as catalyst to study its reacting potential as a homogeneous base catalyst. The initial part of this project studied the optimum conditions to extract crude sea mango oil. It was found that the content of sea mango sea mango oil was 55%. This optimum amount was obtained by using 18 g of grinded sea mango seeds in 250 ml hexane. The extraction was carried out for 24 hours using solvent extraction method. Response surface methodology (RSM) was employed to determine the optimum conditions of the reaction. The three manipulated variables in this reaction were the reaction time, oil to solvent molar ratio, and catalyst wt%. The optimum condition for this reaction determined was 5 hours reaction time, 0.28 wt% of catalyst and 1:35 mol/mol of oil: solvent molar ratio. A series of test were conducted on the final FAME product of this study, namely the FTIR test, GC-FID, calorimeter bomb and viscometer test.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.165-166
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• 2014

The application of particle reaction model in the packed bed process modeling is discussed for iron ore pellet induration process. Combustion of coke breeze in the pellet is estimated by using shrinking unreacted-core model and grain model in which the progress of chemical reaction is described in different concepts. Under the identical inlet gas and solid conditions, the calculation using shrinking core model showed deviated results in terms of temperature profile and conversion fraction, which may imply the significance of selecting proper particle reaction model in consideration of particle characteristics and process operation conditions.

• Mass Spectrometry Letters
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• 제3권4호
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• pp.108-111
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• 2012

An experimental study on the nascent product of the OH heterogeneous reaction with NaCl was performed under dry and wet conditions using a bead-filled flow tube system coupled to a high-pressure chemical ionization mass spectrometer. The ozone concentration in the flow tube for the atomic hydrogen removal was varied in order to control the conversion reaction of molecular chlorine into HCl for the identification of the nascent product. The mass spectrometric observation was that the $O_3$ introduction reduced the concentration HCl, while it increased the concentration of $Cl_2$ and ClO. Based on the experimental results, we suggest that the nascent product of the titled reaction is gaseous $Cl_2$, which is followed by fast conversion into HCl in presence of H. No significant difference in the concentration profile between under dry and wet (RH = 2%) conditions was observed.

• 약학회지
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• 제15권1호
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• pp.24-31
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• 1971

Optimum reaction conditions for the preparation of extra-light magnesium carbonate from bittern by the reaction with sodium carbonate solution was found to be as follows: reaction temperature 33.deg. molar ratio(Mg$^{+2}/CO$^{2-}_{3}$)0.8, reaction time 14 minutes, drying temperature 99.deg. and bittern concentration 17%. While Korean pharmacopeia regulates the bulkiness above 12 mililiters per gm., our experimental result shows above 45 mililiters. Electron microscopic shapes were compared with products prepared under various reaction conditions, and it was found that there exists lighter the powder the more pillar crystalline, the heavier the powder the more amorphous and the intermediate was mixture of them.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3640-3644
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• 2012

An efficient synthetic method for direct Henry reaction catalyzed by a biguanide; namely metformin, as an organosuper-base, between a variety of aromatic and aliphatic aldehydes and nitromethane under neat conditions has been developed. Convenient procedure for removal of the catalyst, chemoselective acquiring of ${\beta}$-nitroalcohols as predominant products, as far as possible short reaction time with excellent conversions are advantages of the developed protocol.

• 한국환경과학회지
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• 제32권3호
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• pp.197-204
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• 2023

This study aims to inactivate Artemia sp. (Zooplankton) in ballast water through the dielectric barrier discharge (DBD) plasma process. The DBD plasma process has the advantage of enabling direct electric discharge in water and utilizing chemically active species generated by the plasma reaction. The experimental conditions for plasma reaction are as follows; high voltage of 9-22 kV, plasma reaction time of 15-600 s, and air flow rate of 0.5-5.5 L/min. The results showed that the optimal experimental conditions for Artemia sp inactivation were 16 kV, 60 s, 2.5 L/min, respectively. The concentrations of total residual oxidants and ozone generated by plasma reaction increased with an increase of in voltage and reaction time, and the concentration of generated air did not increase above a certain amount.

• 폴리머
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• 제32권4호
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• pp.385-389
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• 2008

반응온도의 안정화, 용매 hexafluoropropylene(HFP) 투입량, 그리고 단량체 hexafluoropropylene oxide(HFPO)의 투입속도와 같은 반응조건이 HFPO 음이온 중합의 사슬확장과 사슬이동에 미치는 영향에 대해 연구하였다. Cesium fluoride(CsF)와 tetraethyleneglycol dimethylether(TG)를 사용하여 합성된 음이온 개시제를 이용한 HFPO의 음이온 중합반응에서, 안정적인 반응온도 $-35{\sim}-36^{\circ}C$, 개시제 투입량에 대한 HFP 투입 몰비 31.5, 그리고 HFPO 투입속도 11.57 g/hr의 반응조건으로부터 평균분자량 14800의 고분자량 poly(HFPO)를 얻을 수 있었다. 반면, 불안정한 반응온도, 최적화되지 않은 용매의 투입량과 HFPO 투입속도는 중합물의 사슬이동을 증가시켜 중합체가 원활하게 성장하지 못하였다. 결론적으로, HFPO 음이온 중합반응에서의 사슬확장과 사슬이동은 반응온도의 안정화, 용매의 투입량과 단량체의 투입속도에 매우 민감하게 영향을 받고 있음을 알 수 있었다.

• Environmental Engineering Research
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• 제8권1호
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• pp.31-40
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• 2003

• 대한간호학회지
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• 제30권3호
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• pp.750-763
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• 2000

This study is based on grounded theory methodology by Strauss & Corbin(1998). Ten hospitalized subjects were interviewed for data collection. In the process of data analysis, 'acceptance' is found to be the causal condition, while 'health professionals' skillfulness', 'ward environment', 'history of hospitalization', and 'general conditions' were identified as context, 'felling of relief' as the core phenomenon, 'self-efficacy', 'support of others', and 'life style' as the intermediate situation, 'passive reaction', 'alternative reaction' and 'active reaction' as the strategy and 'stabilization', 'satisfaction', 'hope' and 'carrying out' as consequences. 'Feeling of relief' is found to go through the three stages of recognition-generation-maintenance after the five different patterns. 1) In case the health professionals are skillful, the ward environment is favorable, the general conditions of the patients improved and as a result the feeling of relief is strong, during the first hospitalization, the self-efficacy of the subjects tends to be strong. They proceed toward the goal set for themselves with a renewed hope and active or alternative reaction toward the feeling of relief. 2) The subjects tend to proceed toward the goal set for themselves with a renewed hope and active and alternative reaction toward the feeling of relief in case health professionals are skillful, the ward environment is favorable the general conditions of the subjects improved, self-efficacy is strong, and lifestyle is autonomous, during the second hospitalization even though support of others is merely superficial. 3) The subjects tend to stabilize, and satisfy themselves with the given situation with passive and alternative reaction to the feeling of relief in case health professionals are skillful and the ward environment is favorable but the general conditions worsened and accordingly the feeling of relief, is weak and life style is dependent during the second hospitalization although the subjects' self-efficacy is strong and support of others is specific. 4) The subjects tend to stabilize and satisfy themselves with the given situation with passive and alternative reaction to the feeling of relief in case health professionals are unskillful the ward environment is unfavorable, the general conditions improved, support of others is specific but life style is dependent and self-efficacy is weak during the first hospitalization. 5) The subjects tend to stabilize and satisfy themselves with the given situation in case health professionals are unskillful the ward environment is unfavorable but the general conditions improved support of others is specific and as a result self-efficacy is strong but life style is dependent.

• Structural Engineering and Mechanics
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• 제63권3호
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• pp.347-359
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• 2017

Blast resistant gates are required to be lightweight and able to mitigate extreme loading effect. This may be achieved through innovative design of a gate and its supporting frame. The first is well covered in literature while the latter is often overlooked. The design of supporting frame depends mainly on the boundary conditions and corresponding reaction forces. The later states the novelty and the aim of this paper, namely, the analysis of reaction forces in supporting structure of rectangular steel gates subjected to "far-field explosions". Flat steel plate was used as simplified gate structure, since the focus was on reaction forces rather than behaviour of gate itself. The analyses include both static and dynamic cases using analytical and numerical methods to emphasize the difference between both approaches, and provide some practical hints for engineers. The comprehensive study of reaction forces presented here, cover four different boundary conditions and three length to width ratios. Moreover, the effect of explosive charge and stand-off distance on reaction forces was also covered. The analyses presented can be used for a future design of a possible "blast absorbing supporting frame" which will increase the absorbing properties of the gate. This in return, may lead to lighter and more operational blast resistant gates.