• Korean Journal of Food Science and Technology
• /
• v.31 no.5
• /
• pp.1211-1215
• /
• 1999

The solid yields and color changes of garlic aqueous extracts were determined to study the effects of enzymatic hydrolysis, pH treatment, and addition of organic acids and some organic or inorganic salts. Hydrolysis with commercial polysaccharases resulted in an $15{\sim}20%$ increase in the solid yields, with a greenish color change in the garlic extracts. pH treatment gave it similar effect at the pH range of $4.4{\sim}5.0$. Among the salts and acidulants used, $CaCl_2$, sodium oxalate, tartaric and phosphoric acids were effective for increase in the yield and $K_{4}P_{2}O_{7}$ was effective for both yield increase and control of greening.

• KSBB Journal
• /
• v.14 no.6
• /
• pp.639-642
• /
• 1999

Optimization of the chitosanoligosaccharide production was studied with chitosanase. The optimum conditions for the enzymic reaction have been determined. Enzyme stability was maintained above 90% after 6 days at pH 5.0. The optimum initial reaction rate was appeared in 1.0% of chitosan solution. The production yield of chitosanoligosaccharides was over at 0.4%~2.0% of chitosan. At 4.0% of chitosan solution, however, the production yield was decreased to 64.6%. To increase the yield, stepwise addition of substrate into the reactor was investigated. In this case, the yield was increased from 64.6% to 83.2% and the final concentrations of chitosanoligosaccharide was 12.26 mg/mL. By TLC analysis, most of the chitosanoligosaccharides produced were 3-5 mers.

• Elastomers and Composites
• /
• v.34 no.4
• /
• pp.350-359
• /
• 1999

Conversion and oil-yield of a used automotive tire sample in supercritical decomposition and extraction for three solvents such as water, 28% ammoina solution and ammonia, were compared. Supercritical extraction with ammonia gave the highest conversion and oil-yield at the same temperature and pressure. In this paper, supercritical ammonia was used as major solvent and tetralin acting as hydrogen-donor, was used as cosolvent. As the amount of tetralin increased, oil-yield was Increased. When a tire sample was extracted by supercritical ammonia, oil-yield was 48.8% at $280^{\circ}C$, 22.3MPa. But when the weight ratio of tetralin to tire sample (weight of tetralin/weight of tire sample) was 5, oil-yield was 61.2% at $280^{\circ}C$ and 22.3 MPa. These phenomena indicate that as radicals produced in supercritical decomposition become stable, the polymerization and the second decomposition of products may be inhibited. Supercritical extraction of a tire sample swollen by tetralin gave high oil-yield although the amount of tetralin was a little.

• Journal of the Korean Wood Science and Technology
• /
• v.42 no.6
• /
• pp.653-658
• /
• 2014

This research was carried out to investigate equilibrium moisture content (EMC) of wood in outdoor locations in Korea. EMC was calculated using Hailwood-Horrobin equation for 73 different locations in Korea using the 1981 to 2010 climate normal data obtained from the Korea Meteorological Admnistration (KMA). Daegu showed the lowest values of EMC (11.5), and the highest EMC values (15.8) was found in Heuksando. Considering the season effect, summer (June, July, August) showed the highest values 15.3, followed by autumn (September, October, November) 13.7, winter (December, January, February) 12.2, and spring (February, March, April) 12.0. Monthly EMC showed the lowest values 11.6 in April and July showed the highest EMC values 16.1. The smallest changes in monthly EMC were found in Jeju island and Heuksando showed the largest values 8.7. A proper wood drying based on average EMC is more required in the regions with larger variation in EMC.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.11a
• /
• pp.107.2-107.2
• /
• 2011

억새는 척박한 토양 조건에서도 쉽게 자라며 관리가 용이하다는 장점이 있어 바이오에너지 작물로 주목을 받고 있다. 억새는 주로 Miscanthus sacchariflorus(물억새)와 Miscanthus sinensis(참억새) 그리고 두 억새의 잡종인 Miscanthus giganteus로 구분되며, 최근 기존의 억새보다 생체량을 크게 늘린 거대억새가 개발되기도 하였다. 본 실험에서는 우리나라 전역에서 가장 흔하게 볼 수 있는 물억새와 참억새를 유동층 반응기를 이용하여 급속열분해 하였다. 본 연구의 목적은 억새로부터 얻은 바이오원유와 나무로부터 얻은 바이오원유의 특성을 비교하고, 시료투입속도의 변화를 주어 억새로부터 얻은 바이오원유의 수율과 특성을 알아보고자 함이다. 시료의 투입속도는 200g/h, 300g/h, 500g/h, 1000g/h로 변화를 주었으며, 반응온도($500^{\circ}C$), 공탑속도(0.19m/s), 응축기온도($10^{\circ}C$)는 매 실험마다 동일하게 유지하였다. 수집한 바이오원유는 공업분석을 통해 연료로서의 가치를 알아보았다. 목재를 급속열분해 한 경우 바이오원유의 수율은 56.03wt.%로 동일한 조건에서 억새를 급속열분해 한 경우 보다 약 6wt.%가량 높았다. 바이오원유의 발열량은 큰 차이가 없었으나 수분과 점도에서 큰 차이를 보였다. 투입속도가 증가할수록 바이오원유의 수율은 증가하는 경향을 보였으며, 시간당 1000g을 투입하였을 때는 수율이 감소하였으나 수율의 변화는 크지 않았다. 투입속도가 증가하는 경우 바이오원유의 고위발열량과 점도는 감소하고 수분이 증가하는 경향을 보였다.

• Clean Technology
• /
• v.13 no.1 s.36
• /
• pp.46-53
• /
• 2007

We depolymerized PET in supercritical methanol and observed the yield of DMT at various reaction conditions. At subcritical state below $240^{\circ}C$, the yield of DMT was very low, about only 50%. It increased dramatically to 80% at supercritical state above $260^{\circ}C$, thereafter the increasing rate was reduced significantly. Similarly, at subcritical state of 6.89 MPa, the DMT yield was only 50%, but it increased abruptly to 85% at supercritical state of 10.34 MPa, yielding no further increase above the pressure. Within 10 minutes after the beginning of the reaction, the DMT yield reached 80%, indicating that the significant portion of the reaction has proceeded, and then, the yield increased slowly. The methanol/PET ratio of 8 showed the maximum DMT yield. We found the optimum depolymerization condition fur PET methanolysis is temperature $300^{\circ}C$, pressure 10.34 MPa, reaction time 40 minutes, and methanol/PET ratio of 8.

• Korean Chemical Engineering Research
• /
• v.46 no.1
• /
• pp.189-193
• /
• 2008

In this study, the effect of reaction conditions on the transesterification of soybean oil and methanol was investigated in a high-pressure-fixed-bed-reactor-system with zinc aluminate catalysts. Without catalysts, high-pressure-reaction at $300^{\circ}C$ and 1,200 psi brought 19% yields of methyl esters, which was caused by the approach of reaction condition to supercritical point of methanol. However, except the specific reaction condition, the yields in the reaction with no catalyst were very low below 4.5%. The zinc aluminate was prepared as catalyst by coprecipitation and characterized with $N_2$ gas adsorption/desorption and X-ray diffraction. With catalyst, the effect of the reaction parameters such as temperature, pressure, and molar ratio of reactants on biodiesel production was demonstrated. The higher temperature, pressure, and methanol molar ratio to soybean oil, the more yields of methyl esters. It was proved that among the reaction parameters, the reaction temperature be the most influential variable on methyl ester yields.

• Korean Journal of Food Science and Technology
• /
• v.37 no.5
• /
• pp.730-735
• /
• 2005

Possibility of using low-molecular weight alginate as a wall material for encapsulation of fish oil was investigated. Encapsulation yield increased with increasing calcium chloride concentration up to 5% and was maintained thereafter, whereas slightly increased with increasing sodium alginate concentration up to 1.25% and decreased dramatically thereafter; emulsifier concentration had no effect on encapsulation yield. Loading efficiency increased with increasing content of core material. Encapsulation yields of low- and high-molecular weight alginates were similar, indicating low-molecular weight alginate can be used as wall material for encapsulation of fish oil.

• Applied Biological Chemistry
• /
• v.40 no.5
• /
• pp.395-399
• /
• 1997

Lintnerization properties and yield of enzyme-resistant starch in maize starches with different amylose content were investigated. Hydrolytic patterns of starches showed two distinct stages. With decreasing the amylose content, hydrolysis extents of starch increased. X-ray diffraction patterns of Amloca, PFP and commercial maize starch were the A crystalline type, and those of Amaizo 5 and Amylomaize VII were the B crystalline type. As acid hydrolysis time increased, the relative crystallinity of starches increased. After heating-cooling treatment was repeated up to 4 times, the yield of RS increased with increasing the amylose content. The yields of RS in lintnerzed maize starches decreased with acid treatment.

• Korean journal of food and cookery science
• /
• v.15 no.4
• /
• pp.418-425
• /
• 1999

The characteristics and yield of resistnat starch (RS) in waxy starches which were treated with 0.1N HCl were investigated. Hydrolysis rate of waxy starches were 0.32-0.88%. The yields of RS in waxy maize and waxy barley starches increased with acid treatment time up to 12hr and then decreased. The yield of RS in waxy rice starches increased with acid treatment up to 8hr and then decreased. The hydrolysis and yield of RS were different depending upon the varieties of starch source. Autoclaved normal maize starch showed a gel-like structure, but autoclaved normal maize starch showed crystal particle on the surface by SEM. The shape of autoclaved resistant starch was not different from acid treated ones. X-ray diffraction patterns of native and acid treated starches were all A-types. X-ray diffraction patterns of autoclaved waxy maize starches showed amorphous structures, however, those of RS showed all completely crystalline structure.