• Journal of the Korean Wood Science and Technology
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• v.46 no.4
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• pp.380-392
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• 2018

The importance of polysaccharides is increasing globally due to their role as a significant source of dietary prebiotics in the human diet. In the present study, in order to maximize the yield of crude polysaccharides from Pinus densiflora, response surface methodology (RSM) was used to optimize a two-stage extraction process consisting of steam explosion and water extraction. Three independent main variables, namely, the severity factor (Ro) for the steam explosion process, the water extraction temperature ($^{\circ}C$), and the ratio of water to raw material (v/w), were studied with respect to prebiotic sugar content. A Box-Behnken design was created on the basis of the results of these single-factor tests. The experimental data were fitted to a second-order polynomial equation for multiple regression analysis and examined using the appropriate statistical methods. The data showed that both the severity factor (Ro) and the ratio of water to material (v/w) had significant effects on the prebiotic sugar content. The optimal conditions for the two-stage process were as follows: a severity factor (Ro) of 3.86, a water extraction temperature of $89.66^{\circ}C$, and a ratio of water to material (v/w) of 39.20. Under these conditions, the prebiotic sugar content in the extract was 332.45 mg/g.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.511-516
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• 2005

Sorbitan methacrylate was synthesized from sorbitan dehydrated from D-sorbitol using an immobilized lipase. To optimize the enzymatic synthesis of sorbitan methacrylate, response surface methodology was applied to determine the effects of five-level-four-factors and their reciprocal interactions on sorbitan methacrylate biosynthesis. A total of 30 individual experiments were performed, which were designed to study reaction temperature, reaction time, enzyme amount and substrate molar ratio. A statistical model predicted that the highest conversion yield of sorbitan methacrylate was 100%, at the following optimized reaction conditions: a reaction temperature of 43.06 $^{\circ}C$, a reaction time of 164.25 mins., an enzyme amount of 7.47%, and a substrate molar ratio of 3.98:1. Using these optimal factor values under experimental conditions in four independent replicates, the average conversion yield reached 98.7%${\pm}$1.2% and was well within the value predicted by the model.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.904-909
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• 2005

To optimize the removal of free fatty acid in crude vegetable oil, response surface methodology was applied to determine the effects of five level-four factors and their reciprocal interactions on removal of free fatty acid. A total of 30 individual experiments were performed, which were designed to study reaction temperature, reaction time, catalyst amount and methanol amount. A statistical model predicted that the highest removal yield of free fatty acid was 99.8%, at the following optimized reaction conditions: a reaction temperature of 64.99$^{\circ}C$, a reaction time of 36.20 mins., an catalyst amount of 13.01% (w/v), and a methanol amount of 15% (v/v). Using these optimal factor values under experimental conditions in three independent replicates, the average removal yield was well within the value predicted by the model.

• KSBB Journal
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• v.28 no.6
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• pp.366-371
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• 2013

Ethanol productions were performed by separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) processes using seaweed, Enteromorpha intestinalis (sea lettuce). Pretreatment conditions were optimized by the performing thermal acid hydrolysis and enzymatic hydrolysis for the increase of ethanol yield. The pretreatment by thermal acid hydrolysis was carried out with different sulfuric acid concentrations in the range of 25 mM to 75 mM $H_2SO_4$, pretreatment time from 30 to 90 minutes and solid contents of seaweed powder in the range of 10~16% (w/v). Optimal pretreatment conditions were determined as 75 mM $H_2SO_4$ and 13% (w/v) slurry at $121^{\circ}C$ for 60 min. For the further saccharification, enzymatic hydrolysis was performed by the addition of commercial enzymes, Celluclast 1.5 L and Viscozyme L, after the neutralization. A maximum reducing sugar concentration of 40.4 g/L was obtained with 73% of theoretical yield from total carbohydrate. The ethanol concentration of 8.6 g/L of SHF process and 7.6 g/L of SSF process were obtained by the yeast, Saccharomyces cerevisiae KCTC 1126, with the inoculation cell density of 0.2 g dcw/L.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.342-348
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• 2001

This study was conducted to obtain granular crystalline gypsum that can be used as raw material for plaster boards or cements from waste Plaster board. We could disintegrate preferentially gypsum to gypsum needle in 10${\mu}{\textrm}{m}$ or less size among the contents of waste plaster board (gypsum, paper, fiber, and inorganic material .etc.) by hydration afterwards the dehydration of crushed waste plaster board. In this case, the optimum conditions for minimizing the size of gypsum were dehydration rate of 75%~ 85%, hydration concentration of 10~20%, agitation speed of 250~400rpm, crushing size of 2cm or less. Gypsum of 98.21% grade was recovered with 99.0% yield from under screenings of 325mesh wet screening which followed by the dehydration-hydration process performed in the conditions of dehydration rate of 80%, hydration concentration of 15%, agitation speed of 300rpm, crushing size of 2cm or less. Subsequently, Plate-like Crystalline gypsum of is 151${\mu}{\textrm}{m}$ size and the grade of 99.49% with the Yield of 98.0% from the upper screenings of 270mesh wet screening carried out after the re-crystallization of the recovered gypsum needle slurry.

• The Korean Journal of Ecology
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• v.19 no.2
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• pp.165-178
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• 1996

We investigated the role of competition in adaptation to varying water availability levels for two ecotypically-differentiated populations of Impatiens pallida found naturally in low- vs. high-water environments. In a greenhouse experiment, seedlings were grown in pure cultures at two densities (n=1 and 2 plants per pot) and in mixed cultures (n=2) under low-, medium- and high-water treatments. The two populations were shown to be genetically distinct across the range of environmental conditions in the greenhouse experiment, confirming previous findings. The two populations had similar morphological responses to density and water availability in pure cultures and mixtures, but the population from the high-water environment showed a greater growth response to high water availability than did the population from the low-water environment and the difference in growth between the two populations decreased from the high-water to low-water treatment. Relative competitive ability of two populations were compared under three different water treatments and two densities. Differential response to watering treatment and density were not reflected in a difference in relative competitive ability. Relative yield totals were significantly greater than 1 overall. The niche differentiation suggested by RYTs>1 may be responsible for the lack of differential competitive effects observed for populations in the three vatering treatments.

• Journal of the Korean Applied Science and Technology
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• v.16 no.3
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• pp.211-216
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• 1999

This study was conducted to recover the aluminum from water treatment plant sludge containing alumina. The optimum reaction conditions about chlorination of sludge with $NH_4Cl$ are as follows: the weight ratio of sludge to $NH_4Cl$ is 4, the reaction time is 60min, and the temperature is $300^{\circ}C$. And the result of leaching time test showed that the highest yield of alumina at $160^{\circ}C$ was 96% but the result of leaching test at $160^{\circ}C$ was little better than that of leaching test at $100^{\circ}C$ while the leaching concentration of HCl was 4N. The optimum reaction conditions of chlorinated sludge with $NH_4Cl$, gave the highest yield of 95.41% based on aluminum.

• Fashion & Textile Research Journal
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• v.7 no.1
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• pp.96-100
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• 2005

The bleaching is one of the worst factors which leads to the damage of the human hair. The cuticle of the human hair is injured by the alkali that is one of the chief ingredients of a bleaching agent. The alkali component of the bleaching solution chemically reacts with human hair, reducing the tenacity and dissolving the cuticle layer. The purpose of this study is to examine the effects of bleaching time and temperature on the physical properties and morphology. The results were as follows. 1. The stress-strain curves for human hair indicated the three distinct regions, such as Hookean region, Yield region and post-Yield region. The tenacity of hair is reduced gradually with an increase of bleaching time. Under these same conditions, elongation of the hair increased. 2. The greatest drop in tenacity for hair occured between $40^{\circ}C$ and $60^{\circ}C$ of bleaching temperature. 3. Compared with the virgin hair, bleached hair showed a slower rate of weight reduction in the TGA thermogram. The rate decreased gradually as the bleaching time and temperature increased. 4. As the bleaching conditions reached time and temperature extremes, the human hair cuticle became more damaged. The cuticle layers seemed to have dissolved, as seen in the SEM photographs.

• Korean Journal of Microbiology
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• v.28 no.4
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• pp.345-350
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• 1990

In order to ferment D-xylose directly to ethanol, Yeasts capable of utilizing D-xylose as a sole carbon source and energy source were isolated from soil, sawdust and rotten woods. Among them, the yeast strain, which showed the best ability to produce ethanol, was identified as Candida sp. L-16 isolated from rotten woods. The optimal conditions for production of ethanol were 60rpm of agitation speed, 28j.deg.C of temperature, 4.5 of initial pH and 5% of D-xylose concentration. Ethanol production was reached to maximum state for 4 days culture. Under these optimal conditions, the maximum ethanol concentration and theoretical ethanol yield were 2.4%(v/v) and 74.4% of theoretical value, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.2
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• pp.161-170
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• 2008

Interest is growing in applying simulation models for the South Texas conditions, to better assess crop water use and production with different crop management practices. The Environmental Policy Integrated Climate (EPIC) model was used to evaluate its application as a decision support tool for irrigation management of com (Zea mays L.) in South Texas of the U.S. We measured actual crop evapotranspiration (ETc) using a weighing lysimeter, soil moisture using a neutron probe, and grain yield by field sampling. The model was then validated using the measured data. Simulated ETc using the Hargreaves-Samani equation was in agreement with the lysimeter measured ETc. Simulated soil moisture generally matched with the measured soil moisture. The EPIC model simulated the variability in grain yield with different irrigation regimes with $r^2$value of 0.69 and root mean square error of $0.5\;ton\;ha^{-1}$. Simulation results with farm data demonstrate that EPIC can be used as a decision support tool for com under irrigated conditions in South Texas. EPIC appears to be effective in making long term and pre-season decisions for irrigation management of crops, while reference ET and phenologically based crop coefficients can be used for inseason irrigation management.