• Resources Recycling
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• v.21 no.2
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• pp.41-46
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• 2012

An investigation on the recovery of nickel from spent electroless plating solutions has been performed using the electrowinning method. For this aim, nickel in spent electroless plating solutions was separated as nickel hydroxide through the addition of caustic soda. Nickel hydroxide was completely dissolved with sulfuric acid and an electrolysis was performed for electrowinning of nickel from nickel solutions. As a result, it was found that more than 99% of nickel in spent electroless plating solutions could be precipitated as nickel hydroxide above pH 10 with the addition of caustic soda. As far as the current efficiency in electrowinning of nickel was concerned, it was decreased with increase in the current density.

• Journal of Sericultural and Entomological Science
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• v.18 no.1
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• pp.27-39
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• 1976

In this study several kinds of spun silk yarn-synthetic filament compounded yarn was manufactured, and several fabrics woven from above mentioned silk compound yarn for evaluation of serviceability as clothing materials. The following results were obtained: 1. Degumming agents are in the order of sodium silicate, sodium hydroxide, sodium carbornate, soap and water. 2. When the concentration of sodium hydroxide is exceeded 3%, degradation of floss silk property is resulted because of excessive dissolving out of silk protein. 3. Degumming effect is much improved by concentration of degumming agent and less by its treating time. 4. Simultaneous application of more the 2 kinds of degumming agent is desirable for improvement of floss silk. 5. Application of natural organic acid brings very good results in keeping original scooping and color of the silk. 6. Load and elongation it increased by compound with synthetic filament yarn. 7. Even the evenness of compound yarn is largely dependent on the quality of floss silk and extent of degumming, the C.V.% of silk compound yarn in the experiment was 8-12%. 8. Single bath dyeing technique was impossible for their cloth, and dyeing was performed in 2 bath system separately for silk and synthetic fiber. 9. Shrinkage ratio due to the dyeing of fabric was 23% in case of polyester and spun silk fabric. 10. The final woven cloth can be applicable to (a) Blouse in care of thin cloth (compound silk fabric) (b) Korean costume for women in case of thick cloth. (compound hand spun silk fabric)

• Applied Chemistry for Engineering
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• v.23 no.4
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• pp.399-404
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• 2012

The objective of this study was to investigate the efficient pretreatment method for bioethanol production from rice hull. Ammonia and sodium hydroxide as an alkaline solution and dilute sulfuric acid as an acidic solution were used in a batch reactor under high-temperature and high-pressure conditions. The highest enzymatic saccharification efficiency of 82.8% and ash removal rate of 94.7% were obtained in the dilute sulfuric acid treated sample after the sodium hydroxide solution treatment. The enzymatic saccharification efficiencies and ash removals of pretreated rice hull samples have very similar variation tendency. This means that the maximum obstructive factor for the enzymatic saccharification of rice hull is the ash (silicate) content in biomass. The findings suggest that the combined sodium hydroxide-dilute sulfuric acid treatment system under high-temperature and high-pressure conditions is a promising pretreatment method to enhance the enzymatic saccharification of the silica-rich biomass.

• Resources Recycling
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• v.27 no.2
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• pp.38-47
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• 2018

Integrated gasification combined cycle (IGCC) is a next generation energy production technology that converts coal into syngas with enhanced power generation efficiency and environmental performance. IGCC produces almost coal gasification slag as the solid by-product. IGCC slag is generated about 140,000 tons for a year although recycling of it is still in the early stages. We evaluated the potential of IGCC slag which is generated from a pilot plant in South Korea as an alkali-activated cement. Samples which were activated with the combined activator of sodium silicate solution and caustic soda had an average compressive strength of 4.5 MPa, showing expansion. Expansion of the alkali-activated slag was presumed to be caused by free CaO in the slag, although it was not detected by the ethylene glycol method. Samples that were activated with the combined activator of sodium aluminate and caustic soda had an average compressive strength of 10 MPa. Hydroxy sodalite and $C_3AH_6$ were found to be the new crystalline phases. IGCC slag can be used as an alkali-activated material, but the strength performance should be improved with proper mix design approach to calculate optimum proportions which can alleviate the expansion issue at the same time.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2003.04a
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• pp.78-82
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• 2003

셀룰로오스계 재생섬유 중 가장 먼저 개발된 Viscose rayon은 셀룰로오스 펄프를 17-18%의 가성소다 수용액에 팽윤시켜 알칼리 셀룰로스를 만든 뒤 이황화탄소(CS$_2$)에 반응시킨 후 방사하여 제조하며 흡습성, 제전성, 드레이프성 및 광택이 우수한 쾌적성 섬유이다. 그러나 탄성 회복율이 좋지 않으며 강력이 적고 특히 습윤시의 강력 저하의 단점이 있을 뿐만 아니라 제조과정에서 사용하는 이황화탄소의 환경 유해성이 큰 문제점으로 지적되고 있어 선진국들이 점차 설비를 폐쇄하거나 개도국으로 이전하고 있는 실정이다. (중략)

• Journal of Chest Surgery
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• v.6 no.2
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• pp.219-224
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• 1973

82 cases of esophageal stenosis due to lye solution in our hospital, which is surgicallly treated with retrosternal esophagoplasty were reported. female was 2 times more then male and average age is 30 years old. Dyphagia and precordial pain were chief complaint. In this technique, jejunum, right and left colon were substituted for constricted esophagus. Postoperative complication rate 14.6%, mortality rate due to other complication were 21.9% but had not seen in this operative technique.

• Proceedings of the Membrane Society of Korea Conference
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• 2005.11a
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• pp.285-286
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• 2005

• Journal of Mushroom
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• v.13 no.2
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• pp.85-91
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• 2015

This study was initiated to evaluate ethanol production by a Korean isolate of white rot fungus Irpex consors. It was found that the fungus could produce ethanol by converting glucose, mannose, xylose, and cellobiose under semi-aerobic condition with yields of 0.23, 0.19, 0.21, and 0.17 g ethanol per g sugars, respectively. Furthermore, the strain produced ethanol by simultaneous saccharification and fermentation of rice straw treated with steam pressured boiling water, 3% NaOH, and 3% $H_2SO_4$ with maximum yields of 0.12, 0.15, and 0.19 g ethanol per g rice straw, respectively. These results suggested that I. consors could produce ethanol from the components of cellulose and hemicellulose including glucose, mannose, xylose, cellobiose as well as rice straw treated with steam pressured boiling water, dilute sodium hydroxide, and dilute sulfuric acid. This is the first report that I. consors mycelia produce ethanol from various sugars and lignocellulosic substance including rice straw.

• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.86-92
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• 2017

A process, which converts carbon dioxide contained in the flue gas of coal-fired power plants to sodium bicarbonate, was studied experimentally and numerically. In this process, the carbon dioxide reacts with sodium hydroxide which is produced through saline water electrolysis. A bench scale reactor system was prepared for experiments of this process and numerical process modeling was performed for the bench scale reactor system. Comparing the process modeling results with the experimental data, responsibility of the process modeling was confirmed. Using this model, commercial scale process was simulated. Mass and energy balance of this process were calculated. Temperature profile in the reactor and carbon dioxide removal rate were obtained.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.205-211
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• 2010

The water-sewage cohesion agent(polyaluminumchloride(PAC)) and NaOH were used to synthesize $Al(OH)_3$. For various additions of NaOH, characteristics of the synthesized $Al(OH)_3$ was analysed by XRD, SEM and PSA. According to XRD analysis, small amount of NaOH(NaOH:PAC=15g:100g) resulted in amorphous form of $Al(OH)_3$. By increasing NaOH(NaOH:PAC=20g:100g), the mixture of gibbsite(37%), bayerite(35%) and boehmite(28%) were produced. By adding more NaOH(NaOH:PAC=25g:100g), binary mixtures of gibbsite(67%) and bayerite(33%) were formed. Finally, high addition of NaOH(NaOH:PAC=30g:100g) gave the high concentration of gibbsite(gibbsite:bayerite=83:17). Also, SEM analysis indicated that the product featured the plate form with 20 and 30g of NaOH addition. Furthermore it was found that the particle size of the product decreased with the addition of NaOH.