• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.747-753
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• 2013

The physicochemical properties of sweet potato (SP) starches reclaimed from an SP-processing sludge without freezing (RC/NF) and with freezing (RC/FR) were investigated. Lab-isolated (LI) SP starch, as a control, were prepared from raw SP. RC/NF and RC/FR SP starches were recovered from SP-processing sludges by the repeated sieving and washing procedure. The total starch contents and amylopectin branch-chain distributions did not differ for three SP starches. Relative to LI and RC/NF SP starches (possessing similar physicochemical characteristics), the apparent amylose and phosphorus contents, swelling factor, and pasting viscosity were reduced for RC/FR SP starch. However, the freezing treatment altered X-ray diffraction pattern (at $5.5^{\circ}$, $11-12^{\circ}$, and $24^{\circ}$ $2{\theta}$) of RC/FR SP starch, which likely increased its gelatinization peak and completion temperatures. Its amorphous region in total diffractogram was reduced, resulting in the enhanced relative crystallinity. Overall results suggested SP starches recovered from an SP-processing sludge would have the potential to replace commercial SP starch products.

• KSBB Journal
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• v.5 no.1
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• pp.59-67
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• 1990

Enzymatic hydrolysis of insoluble cellulose was performed in a bubble column with tangential flow ulrafiltration membrane unit. The reactor was operated in a batch mode as well as semi-continuous and continuous with continuous removal of products through the tangential flow ultrafiltration membrane. The optimum superficial gas velocity was 1-3cm / sec so as to avoid bubble coalescence and enzyme denaturation. In continuous and selni-cotinuous process, the conversion was gradually increased but the total reduced sugar concentration was drcastically dereased with the dilution rate. It was concluded that the bubble column attaching tangential flow ultrafiltration membrane unit was effective on continuous hydrolysis of cellulose and recovery of enzyme.

• Resources Recycling
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• v.19 no.6
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• pp.77-85
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• 2010

This study was carried out to develop a process flow sheet for recovering valuables (gold and high purity silica) from the gold mine tailings containing 1.7 g/ton of gold and 79.48 wt.% $SiO_2$. Float-sink tests using heavy liquids was conducted to explore the possibility of recovering gold by gravity separation. Hydrocyclone, froth flotation, and triboelectrostatic separatoin tests were conducted to recover high purity silica from the gold mine tailings. The results of float-sink tests showed that particles containing 5.58 g/ton of gold could be obtained at 2.72 specific gravity, but with very low yields around 3%. Meanwhile, all tests with hydrocyclone, froth flotation, and triboelectrostatic separation showed that high purity silica with $SiO_2$ content over 90% could be obtained. The purity could be improved further up to about 94% by employing several recleaning steps in the froth flotation and triboelectrostatic process.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.1
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• pp.33-39
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• 2022

Batch experiments were conducted to find out the effects of various types of magnesium compounds on phosphorus recovery by magnesium ammonium phosphate (MAP) crystallization. The phosphorus recovery from the centrate of anaerobic digested sludge was performed using magnesium chloride, magnesium hydroxide and magnesium oxide under different pH (7.5, 8.0 and 8.5) and Mg/P molar ratio (1.0, 1.5, 2.0, 2.5) conditions. The phosphorus recovery rate increased with increasing pH and Mg/P molar ratio in all magnesium compounds. At pH 7.5, magnesium oxide showed the highest phosphorus recovery rate, followed by magnesium hydroxide and magnesium chloride. However, at pH 8.5, more than 90% of phosphorus recovery rate was obtained in all Mg/p molar ratios. Thus, it is expected that magnesium hydroxide and magnesium oxide are able to replace magnesium chloride as a magnesium source in terms of phosphorus recovery efficiency and cost.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.3
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• pp.261-267
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• 1999

Pot experiments were conducted to evaluate the phosphorus (P) availability with cropping in soils where P were highly accumulated. Bray 1-P contents of the used three soils were 584, 695 and $1043P\;mg\;kg^{-1}$, respectively. Corn ${\rightarrow}$ Chinese cabbage ${\rightarrow}$ Chinese cabbage ${\rightarrow}$ corn were sequentially grown from 1996 to 1998. P fertilizer was applied at three levels of 0 (P0), recommended application rate (P1), and double of recommended application rate (P2). At the end of each crop growth, available P content was determined by methods of Bray 1-P, Olsen-P and Lancaster-P. The growth of crops were not significantly affected by the rates of P applications. The relative yields of PO treatment were more than 88% of P1 treatment. The recoveries of added phosphorus were relatively low due to the high content of available phosphorus in soils. Although available phosphorus contents decreased through cropping, the concentration of soil available phosphorus was maintained high level even after the final cropping. In the case of P0 treatment in the three soils, the residual concentration was in the range of $410{\sim}610mg\;kg^{-1}$ for Bray 1-P, $284{\sim}410mg\;kg^{-1}$ for Olsen-P and $368{\sim}524mg\;kg^{-1}$ for Lancaster-P. The amount of soil available phosphorus decreased during the experiments was linearly regressed with high significance to the amount of P taken up by crops. The regressions of soil 1 as follow, Bray 1-P : y=149.7x=102.7, Lancaster-P : y=209.2x-140.2, Olsen-P: y=60.8x=19.9. The decrease rate of available phosphorus in the P0 treatment with cropping was described by an equation of first-order chemical reaction. The equation of soil1 was as follow: Bray 1-P: In(C)= -0.12N + 6.96 r=-0.991, Lancaster-P: In(C)= -0.14N = 6.88 r= -0.938, Olsen-P: In(C)= -0.07N = 6.37 r= -0.959. The rate constants seemed to be affected by ply, sand and silt content, and exchangeable $Ca^{2+}$ concentration. The times of cropping needed to reduce the content of available P to half of the initial or to the index level could be predicted by using that equation.

• Fire Science and Engineering
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• v.2 no.3
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• pp.58-64
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• 1988

본 강좌는 소방공학분야를 기초과정에서부터 전문성에 이르기까지 공부하는 데에 관심을 갖거나, 산발적으로 또는 부분적으로 상당한 지식은 있으나 보다 이해의 체계화를 추구하고자 하는 회원들을 위하여 연재물의 성격으로 마련된 것이다. 따라서 본 강좌는 매우 교과서적 성격으로 편집될 것이다. 본 강좌의 내용은 본 학회의 회원중 사계의 전문인들이 협동하여 적절히 번갈아 집필함으로써 향후 연재회수에 제한 없이 게재될 것이며, 관심 있는 회원들에게 다소라도 도움이 되었으면 한다.

• Fire Science and Engineering
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• v.1 no.1
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• pp.57-66
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• 1987

본 강좌는 소방공학분야를 기초과정에서부터 전문성에 이르기까지 공부하는 데에 관심을 갖거나, 산발적으로 또는 부분적으로 상당한 지식은 있으나 보다 이해의 체계화를 추구하고자 하는 회원들을 위하여 연재물의 성격으로 마련된 것이다. 따라서 본 강좌는 매우 교과서적 성격으로 편집될 것이다. 본 강좌의 내용은 본 학회의 회원중 사계의 전문인들이 협동하여 적절히 번갈아 집필함으로써 향후 연재회수에 제한 없이 게재될 것이며, 관심 있는 회원들에게 다소라도 도움이 되었으면 한다.

• Electric Engineers Magazine
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• v.247 no.3
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• pp.18-21
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• 2003

ESCO는 제3자의 에너지사용시설에 선투자한 후 이 투자시설에서 발생하는 에너지절감액으로 투자비와 이윤을 회수하는 기업으로서 에너지사용자는 투자 위험없이 에너지절약 시설투자가 가능하고 ESCO는 투자수익성을 보고 투자위험을 부담하는 벤처형사업으로 정의된다.

• Fire Science and Engineering
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• v.2 no.2
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• pp.59-64
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• 1988

본 강좌는 소방공학분야를 기초과정에서부터 전문성에 이르기까지 공부하는 데에 관심을 갖거나, 산발적으로 또는 부분적으로 상당한 지식은 있으나 보다 이해의 체계화를 추구하고자 하는 회원들을 위하여 연재물의 성격으로 마련된 것이다. 따라서 본 강좌는 매우 교과서적 성격으로 편집될 것이다. 본 강좌의 내용은 본 학회의 회원중 사계의 전문인들이 협동하여 적절히 번갈아 집필함으로써 향후 연재회수에 제한 없이 게재될 것이며, 관심 있는 회원들에게 다소라도 도움이 되었으면 한다.

• Environmental engineer
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• s.175
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• pp.70-75
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• 2001

산업용 보일러에 대해 오일버노에서 가스버너로 설비교체를 하면서 폐열회수, 저공기비 운전 등을 통해 열효율이 6$\~$8$\%$ 정도 향상되었으며 fuel NO의 제거로 질소산화물질은 1/3정도 배출되었다. 지구온난화 물질인 이산화탄소의 배출도 에너지 절감을 통해 6$\~$8$\%$ 정도 절감되었다. 이러한 결과는 국내 산업용 보일러의 효율향상 및 성능개선에 대한 분석적인 적용