• 공업화학
• /
• 제8권2호
• /
• pp.179-190
• /
• 1997

준역청탄, 유연탄, 무연탄 및 국내 무연탄을 포함하는 54종의 석탄회분을 대상으로 화학조성 및 광물분석 그리고 용융온도를 측정하여 화학조성이 용융온도에 미치는 영향을 고찰하였다. 석탄회의 구성 산화물중 CaO와 MgO, 그리고 $Fe_2O_3$가 용융온도를 낮추는 산화물임을 알 수 있었다. $Fe_2O_3$에 의한 용융온도 감소 효과는 환원성분위기에서 증가되었다. 산-염기도에서 염기성분의 함량이 증가할수록 용융온도는 감소하였다. 그러나 산-염기도와 용융온도와의 상관관계는 $Fe_2O_3$/CaO비가 증가함에 따라 낮아졌다. 산화성분위기보다는 환원성분위기에서 용융온도가 낮았으며 이때 분위기 변화에 따른 용융온도차는 $Fe_2O_3$의 함량보다는 $SiO_2/Al_2O_3$비와 밀접한 상관성을 보여주었다. 석탄회의 용융온도(연화)를 예측하기 위한 다중회귀분석결과 산화성분위기에서는 Base/Acid, $Fe_2O_3$/CaO, $SiO_2/Al_2O_3$, $(SiO_2/Al_2O_3){\cdot}(Base/Acid)$ 그리고 환원성분위기에서는 Base/Acid, $Fe_2O_3$/CaO, $SiO_2$, $TiO_2$등을 독립변수로 사용함으로써 비교적 상관성이 높은 관계식을 얻을 수 있었다.

• 한국환경과학회지
• /
• 제17권8호
• /
• pp.919-924
• /
• 2008

The surface properties and adsorption rates of activated carbon modified with acid and base were compared. The distribution ratio of C and C-H on the surface of activated carbon were decreased by modification with acid and base, but the distribution ratio of C-O, C=O, and O=C-O were increased. Base modification damaged the surface of activated carbon more than acid modification, it caused the effect of 6 percent increments of surface area. Adsorption rate model was more suitable to second order equation than first order equation. Adsorption rate was controlled by adsorption in pore better than in surface.

• 약학회지
• /
• 제9권1_2호
• /
• pp.14-17
• /
• 1965

It has been known that the organic base complexes formed with the anionic acid base indicators are highly soluble in non-polar solvents but relatively insoluble in water. In the work reported here the formation of the complex between chloropromazine and bromothymol blue was studied and applied it to the determination of the base. The values to determine the binding ratio of the base with the indicator at pH 3.5 obtained from the application of Job's method of continuous variation and mol ratio method were both 1:1. From the application of this reaction to the determination of the base with carbon tetrachloride as the solvent for the extraction, fairy good results have been obtained.

• Korean Chemical Engineering Research
• /
• 제56권5호
• /
• pp.773-778
• /
• 2018

In-situ transesterification of microalgae lipids using microwave irradiation has potential to simplify and accelerate biodiesel production, as it minimizes production cost and reaction time by direct transesterification of microalgae into biodiesel with microwave as a heating source. This study was conducted to research the effect of microwave irradiation with in-situ transesterification of microalgae under base catalyst condition. The process variables (reaction time, solvent ratio, microwave power) were studied using 2% of catalyst concentration. The maximum yield of FAME was obtained at about 32.18% at the reaction time of 30 min with biomass-methanol ratio 1:12 (w/v) and microwave power of 450 W. The GC MS analysis obtained that the main component of FAME from microalgal oils (or lipids) was palmitic acid, stearic acid and oleic acid. The results show that microwaves can be used as a heating source to synthesize biodiesel from microalgae in terms of major components resulting.

• 농업과학연구
• /
• 제36권2호
• /
• pp.225-232
• /
• 2009

The ratio of saccharification and formation of furans during the acid hydrolysis of agar with oxalic acid and sulfuric acid were examined base on the contents of the agar and acids. The ratio of saccharification in oxalic acid appeared to be 51~59% somewhat higher than 49~61% of sulfuric acid. Formation of the furans during the acid hydrolysis increased proportional to the contents of agar and acid. The relative formation ratio was high 10~47% for furfural (FUR) and 15~29% for hydroxy-methyl furfural (HMF) in 0.5~1.25% sulfuric acid rather than those of oxalic acid. When comparing the removal efficiency of the furans using an alkali treatment, steam stripping and hydrophobic resins, FUR was eliminated 60% by the alkali treatment, 62~90% by steam stripping and 71~75% by Amberlite XAD4 and 7HP, while HMF was removed to low levels of 10.5%, 4~17% and 13~25%, respectively. The loss of reducing sugar was also observed in process of the removal of furans, and the loss rate was the level of 2~4% in alkali treatment, 11~16% in steam stripping and 7~9% in Amberlite resins.

• Journal of Nutrition and Health
• /
• 제30권5호
• /
• pp.529-539
• /
• 1997

The present study was to formulate a computer program to provide a menu based on a food preference survey of families in urban areas. A food preference survey was conducted by individual direct interviews of infants, children and old people in this study. In case other's food preferences were available, food menus considering all age groups could be made. Database III PLUS package was utilized for this study. The dBASE was loaded with a food compostion table of 339 different food items, along with data for amino acids and fatty acids for 171 and 43 food items respectively. Food preference, unit of food, and recommended dietary allowances were also incloded. This meun program system calculates nutrients in selected foods, and menu assessment was composed of several factors inculding energy ratio of carbohydrate : protein : fat, amino acid score, limiting amino acid, polyunsaturated fatty acid/saturated fatty acid(JP/S) ratio and Ca/P ratio.

• Archives of Pharmacal Research
• /
• 제18권5호
• /
• pp.314-319
• /
• 1995

Antacid granules were prepared by agglomeration and powder method in high speed agitation type granulator. The copmositions of the test antacids were sodium bicarbonate nad magnesium carbonate nad a coating material was powder of polyvinylacetal diethyl-aminocacetate (AEA) and an additive material was talc powder. The dissolution characteristics of base from the antacid granules were investigated to evaluate neutralization capacity of hydrochloric profile of base and neutralization behavior, the following results were obtained : The prepared granules showed a pH-dependent dissolution pattern of a base. The dissolution profile of a base was varied with addition of talc powder as well as coating amount of AEA. The relationship between the ratio of dissolution retarded time for 20% and 10% AEA. The relationship between the ratio of dissolution retarded time for 20% AEA coated granules $\theta_{20}/\theta_{10}$ and the diameter reduction of the granules was explained by the rate process of neutralization of hydrochloric acid.

• KSBB Journal
• /
• 제25권5호
• /
• pp.483-489
• /
• 2010

Biodiesel has attracted great attention as an alternative renewable energy source for the replacement of petroleumbased diesel fuel, yet its high production cost due to expensive oil feedstock remainsas the major economical obstacle. In this study, we investigated catalysts and reaction conditions for the acid catalyzed pre-conversion of free fatty acid (FFA) to fatty acid methyl ester (FAME) in cheap low-grade oils of high acid value. The NaOH base catalyzed reaction of vegetable oil of the initial acid value of 2 mg KOH/g led to a high FAME conversion above 95.4%, but the conversion abruptly decreased at higher initial acid values. This base catalyzed reaction was practically ineffective displaying the FAME conversion below 15% even at the initial acid value of 10 mg KOH/g by the severe saponification side reaction. Among the various catalysts studied for the pre-conversion of FFA to FAME, Amberlyst-15 was the most effective in reducing the acid value, and the optimum reaction condition identified was $65^{\circ}C$ with oil to methanol ratio of 1:3 and catalyst concentration of 15% (w/w). As the results, great enhancements in the overall biodiesel conversion were achievable via a consecutive reaction of the acid catalyzed FFA pre-conversion to FAME under the optimal condition obtained with Amberlyst-15 followed by the NaOH base catalyzed reaction, far above the extent which was obtainable by the single NaOH catalyzed reaction.

• 분석과학
• /
• 제5권4호
• /
• pp.433-441
• /
• 1992

국내의 23개 무연탄을 대상으로 석탄회의 화학분석 및 용융특성분석을 수행하여 석탄회의 화학조성과 용융온도와의 상관성을 고찰하였다. 또한 이들 무연탄을 미분탄 연소의 연료로 사용시 야기될 수 있는 slagging, fouling성을 예측하여 보았다. 국내 무연탄회는 대부분 $SiO_2$와 $Al_2O_3$를 80% 이상 함유하고 있는 반면 1% 이하의 적은 양의 $Na_2O$를 함유하고 있으며, 또한 비교적 높은 용융온도를 갖는다. 따라서 이 무연탄들을 미분탄 연소의 연료로 사용시 slagging 및 fouling 발생 가능성은 낮을 것으로 예측되었다. 국내 무연탄회의 용융특성은 base/acid ratio와 비교적 높은 상관성을 갖는 것으로 나타났다.

• 공업화학
• /
• 제8권6호
• /
• pp.985-993
• /
• 1997

구성분이 상이한 2종의 비산회를 대상으로 CaO와 MgO융제의 첨가시 용융온도변화에 대하여 고찰하였다. 용융온도측정을 위하여 ASTM 용융온도측정법과 시차열분석법이 사용되었다. CaO융제의 첨가시 시료에 따라 $111{\sim}294^{\circ}C$의 융점(IDT)강하효과를 얻을 수 있었으며 MgO첨가시에는 $80{\sim}224^{\circ}C$의 융점강하효과를 보였다. Base/Acid Ratio와의 비교에서 CaO flux는 0.7~0.8, MgO flux는 0.3~0.4의 범위에서 가장 낮은 용융온도로 측정되었다. 따라서 적은 첨가량으로도 MgO는 CaO보다 더 효과적인 융제로 작용하였다. 이러한 융제첨가시의 용융온도 변화는 용융성 분석에 보편적으로 사용되어지는 Base/Acid ratio와는 상관성이 없음을 알 수 있었고 $XO-SiO_2-Al_2O_3$ [X=Ca, Mg]삼성분계의 liquidus 온도와도 일치하지 않음을 알 수 있었다. 시차열분석결과와 ASTM용융온도와의 비교에서 용융성과 흐름성(점성)등의 물성이 복합적으로 반영되어 있는 ASTM측정법 보다는 시차열분석이 비산회의 순수한 용융온도를 분석할 수 있는 측정법임을 확인할 수 있었다.