• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.1
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• pp.81-88
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• 2010

Characteristic of hydrogen production was investigated to find the optimum heat pretreatment conditions for the anaerobic fermentation of food waste. The heat pretreatment of food waste enhanced the hydrogen yield due to the increase of soluble chemical oxygen demand (SCOD) and carbohydrate content. This result revealed that the maximum degrees of disintegration of SCOD and carbohydrate content were 55.1% and 223.6%, respectively. On the other hand, the improvement of hydrogen yield was insignificantly affected by heating reaction time at longer than 20 min; the increase of hydrogen yield was only about 7% between 20min and 1 hour. Therefore, the increase of reaction time more than 20min was not necessary.

• Preventive Nutrition and Food Science
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• v.9 no.4
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• pp.330-335
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• 2004

Changes in functional constituents of rice germ prepared using three different heat pretreatments: roasting, steaming and microwave heating, were determined and compared with those of non-treated rice germ. The yield of rice germ oil increased generally and then decreased with increasing time for all three heat pretreatments, although the yields of rice germ oil varied among the three heat pretreatments. There were no major differences in fatty acid compositions among the rice germ oils subjected to the three different heat pretreatments. Levels of $\alpha$-tocopherol in rice germ oil increased up to about 1.5 times at 3 min of roasting and microwave heating, compared to control, and then decreased with increasing treatment time, but $\alpha$­tocopherol concentrations in rice germ oil gradually decreased with increasing steaming time. The contents of three phytosterols ($\beta$-sitosterol, stigmasterol and ergosterol) decreased progressively with increases in roasting and steaming time, while concentrations of the three phytosterols increased up to - 15$\%$ with 3 min of microwave process as compared to control, and then decreased thereafter. Levels of $\gamma$-oryzanol in rice germ oil decreased gradually with increasing time during all three different heat pretreatments. However, levels of $\gamma$ -aminobutyric acid (GABA) in rice germ decreased gradually with increasing roasting time, while those of GABA increased greatly up to about 2 times after 10 min of steaming process, and then decreased slowly thereafter. During microwave heating, the contents of GABA increased at 3 min of treatment time and then decreased. These results suggest that microwave heating may be the most suitable processing method to preserve functional constituents in rice germ.

• Food Science and Biotechnology
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• v.17 no.1
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• pp.118-122
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• 2008

The use of tartary buckwheat flour as a source of dietary rutin has been limited because of the enzymatic degradation of rutin during the dough-making process, which results in a bitter taste. A variety of pretreatment regimes, including heating, steaming, boiling, and extruding, were evaluated in relation to the inactivation of the rutin-degrading enzyme responsible for rutin loss and color change during dough-making. Steaming (120 see), boiling (90 see) buckwheat grains, or extruding (180 rpm/min at $140^{\circ}C$) the flour resulted in the retention of >85% of the original rutin and eliminated the bitter taste in the hydrated flours. In contrast, dry heating at $140^{\circ}C$ for 9 min or microwaving at 2,450 MHz for 3 min did not reduce the rutin loss, and the bitter taste remained. Unlike in the flour, the rutin degradation in water-soaked grains was insignificant at room temperature. Moreover, the samples treated by steaming, boiling, or extrusion were darker and more reddish in color.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.7
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• pp.914-920
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• 2012

We investigated the effects of heat treatment and extraction method on the antioxidant activities of five medicinal plants: Cyperus rotundus, Eucommia ulmoides, Bupleurum falcatum, Achyranthes japonica Nakai, and Akebia quinata. Extraction was performed with only ultrasound, ultrasound after heating at $130^{\circ}C$ for 2 hours, and reflux extraction with distilled water. The phenolic contents of reflux extraction and ultrasound extraction after heating were higher than only ultrasound extraction, and ultrasound extraction after heating samples was higher than reflux extraction except for Eucommia ulmoides and Cyperus rotundus. Total flavonoid content was higher in reflux and ultrasound extraction after heating samples than only ultrasound extraction, except for Cyperus rotundus. ABTS radical scavenging activity was higher in reflux extraction and ultrasound extraction after heating a sample, than only ultrasound extraction. DPPH radical scavenging activity was higher in reflux extraction except for Achyranthes japonica Nakai and Akebia quinata. The reducing power of ultrasound extraction after heating was higher with Achyranthes japonica Nakai. From the results of this study, we can expect to increase the antioxidant activity of medicinal plant extracts by applying suitable extraction and pretreatment conditions on the type of medicinal plant.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.2
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• pp.97-104
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• 2016

In the preparation of Ag-coated Cu flakes using L-ascorbic acid as a reductant for the electroless Ag plating, the effects of pretreatment methods and the reductant concentration on the uniformity of Ag coating layer and the anti-oxidation property of Ag-coated Cu flakes during the heating in air were evaluated. It was found that the removal degree of surface oxide layer during the pretreatment has great influence on the uniformity of Ag coating layer and the formation degree of hole defects in the flakes has slight effect on the anti-oxidation property of Ag-coated Cu flakes. It was also verified that the reductant concentration has great influence on the coverage uniformity and thickness of Ag coating, thus it was could be considered a main process parameter. When the reductant concentration was 0.04 M, high-quality Ag-coated Cu flakes was obtained. When the concentration increased to 0.06 M, however, the anti-oxidation property of Ag-coated Cu flakes became remarkably worse owing to remnant of Cu surface non-coated with Ag by the formation of pure Ag fine particles.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.4
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• pp.362-367
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• 2006

Waste activated sludge(WAS) collected from domestic wastewater treatment plant is biomass that contains large quantities of organic matter. However, relevant literature show that the bio-hydrogen yield using WAS was too low. In this study, the effect of pretreatment of WAS on hydrogen yield was investigated. Pretreatment includes acid and alkali treatments, grinding, heating, ozone and ultrasound methods. After pretreatment organic matters of WAS were solubilized and soluble chemical oxygen demand(SCOD) was increased by 14.6 times. Batch experiments were conducted to investigate the effects of pre-treatment methods and buffer solution, hydrogen partial pressure, and sodium ion on hydrogen production from WAS by using heated anaerobic mixed cultures. Experimental results showed that addition of buffer solution, efficient pre-treatment method with alkali solution, and gas sparging condition markedly increased the hydrogen yield to 0.52 mmol $H_2/g$-DS.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.5
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• pp.563-572
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• 1998

An experimental study of hot filament chemical vapor deposition(HFCVD) has been carried out for the fabrication of diamond thin film. Of particular interest is the measurement of deposition uniformity on large substrates. Experimental apparatus including a vacuum chamber, heating elements, etc. has been designed and manufactured. Deposition profiles for different pretreatment powders and different flow rates have been measured in conjunction with the measurement of substrate temperature distribution on a large substrate surface. As the flow rate increases, deposition rate increases, however, the crystallinity becomes worse. Higher growth rate has been found on the region closer to the center location where substrate temperature is higher. The crystallinity has been improved as gas flow rate decreases. The growth rate and morphology of deposition were identified by SEM and the existence of diamond phase was proved by Raman spectroscopy.

• Analytical Science and Technology
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• v.17 no.4
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• pp.363-367
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• 2004

A simple and convenient digestion method was developed for the determination of heavy metal in polyurethane sample using only nitric acid in open system without heating. This digestion method had prevented loss of volatile elements of Hg and As and reduced the pretreatment time for the sample digestion. The detection limit is lowered over 10 times than that of microwave digestion method. Recoveries in polyurethane material were 108% for As, 96 ~ 99% for Hg, 102 ~ 103% for Cr, 98 ~ 102% for Pb, 86 ~ 90% for Cd, and 90 ~ 93% for Cu.

• Journal of the Korean Wood Science and Technology
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• v.51 no.6
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• pp.447-447
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• 2023

This study aimed to convert underutilized moso bamboo into high-value added products such as fences, interior materials, lighting fixtures, and accessories. Green moso bamboo poles with a diameter of approximately 10 cm and a length of approximately 3.7 m were heat treated at 140℃ using a large-scale kiln. The processing time was meticulously adjusted through various stages, including pretreatment (6-8 hours at 60℃), cooking (8-10 hours at 100℃), steaming (26-30 hours at 120℃), heating (4-6 hours at 140℃), and finally, cooling (below 80℃). A meticulously designed heat treatment process has enabled efficient mass production of moso bamboo poles with improved qualities, including minimal splitting, moisture levels below 3%, and a specific gravity of 1.05. The focus of this study was to present the physical and drying properties, such as color, dimensional change, specific gravity, moisture content, and splitting, observed during the heat treatment process.

• KSBB Journal
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• v.20 no.4
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• pp.317-322
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• 2005

Various recovery methods were investigated to maximize hemicellulose recovery from lignocellulosic material hydrolyzed by pure water. The pretreatment conditions of water hydrolysis were $170\~180^{\circ}C$ and 1 hour of reaction time. The percentage of hemicellulose solubilized increased as the temperature increased from 170 to $180^{\circ}C$. However, significant decomposition of sugar was observed at temperature of $180^{\circ}C$. From the results of water hydrolysis, the total amount of glucan in solid residue and liquid hydrolyzate was close to the total glucan in the original biomass. For hemicellulose, however, there was a significant difference between both contents. To prove this difference, various recovery methods were proposed. From the total sugar accountability (sugar in liquid + sugar in solid), it was confirmed that hemicellulose recovery in the hydrolyzate was increased if the product including both hydrolyzate and solid residue was physically stimulated by such as heating and ultrasound irradiation. This indicated that, in commercial scale processes that much bigger substrate sizes are used and a sufficient amount of leaching solvent can not be used after pretreatment, a significant amount of oligomers could be trapped in the solid matrix.