• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.81-88
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• 2011

This study ascertained the possibility of use of sulfur abstracted from waste sulfur as a construction material through modification process and manufacturing high efficiency modification sulfur with superior quality on dispersibility and hydrophilic in normal temperature. Mechanic, behavior and chemical durability of mortar with added modification sulfur. The results of the study are as follows. The fluidity of mortar mixed with modification sulfur and compressive strength decreased as ratio of mixing of them increases. Flexural, tensile and bond strength of the mortar are also improved and shrinkage of it increases. Especially chemical durability of the mortar showed excellent resistance with the increase of ratio of mixing. Therefore this research has confirmed the modification sulfur can be used as a addmixture for cement.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.05a
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• pp.509-512
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• 2003

폐기물을 대상으로 하는 가스화공정은 환경문제와 에너지효율 문제에 동시에 접근할 수 있는 공정으로서 기존의 연소반응에 근거한 공정들을 점차 대체할 것으로 예측되고 있으며 많은 연구와 기술개발이 현재 진행되고 있다. 가스화용융 기술의 장점은 고유황, 고회분의 저급 석탄, 정유공장 부산물 및 도시폐기물까지도 강화되는 환경규제치를 만족하면서 깨끗한 에너지원으로 활용할 수 있다는 점이며, 발생된 고열량 생성가스의 정제를 통해서 연료로서 재활용이 가능하다는 것이다.(중략)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1572-1578
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• 2007

The specified wastes consist of waste acid, waste alkali, waste oil, waste organic solvent, waste resin, dust, sludge, infectious waste, and others. Among these specified wastes, a great portion is liquid phase wastes. The purpose of this study is to develop the high temperature and high pressure (HTHP) treatment system for decomposition of the liquid phase specified waste (LPSW). For this, we analyzed the physical and chemical properties of the LPSW such as density, proximate analysis, ultimate analysis, heating values, and designed 0.3 ton/day HTHP treatment system. The LPSW tested in this experiment were prepared by adding TCE(trichloroethylene) and toluene to liquid phase waste which was brought into the commercial waste treatment company. The average density of waste oil (25 samples), waste resin (5 samples), and waste solvent (12 samples) was 0.99 g/mL, 0.91 g/mL, and 0.93 g/mL, respectively. And the average lower heating value of waste oil, waste resin, and waste solvent was 8,294 kcal/kg, 5,809 kcal/kg, and 7,462 kcal/kg, respectively. The DRE (Destruction & Removal Efficiency) of TCE and toluene were 99.95% and 99.73% at atmospheric pressure conditions and that were 99.99% and 99.82% at pressurized conditions, respectively. These results showed that TCE/toluene mixtures were properly decomposed over about 99.73% of DRE by the HTHP treatment system and pressurized conditions were more effective to destroy those pollutants than atmospheric pressure conditions. Also these systems could be directly applied to industries which try to treat the liquid phase specified waste within the regulation limit.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1048-1056
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• 2018

Non-edible oil sources (i.e., Palm Acid Oil, waste animal fat) usually contain relatively high amount of free fatty acids (FFA) that make them inadequate for direct base catalyzed transesterification reaction. Enzymatic biodiesel synthesis can solve several problems posed by the alkaline-catalyzed transesterification, and has certain advantages over the chemical catalysis of transesterification, as it is less energy intensive, allows easy recovery of glycerol and the transesterification of glycerides with high free fatty acid contents. In this study, we synthesized biodiesel through enzymatic catalyzed process using high free fatty acid containing waste oil in biodiesel reactor (1 ton/day) and optimized the biodiesel production processes.

• Journal of the Korean GEO-environmental Society
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• v.16 no.4
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• pp.41-48
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• 2015

Coffee consumption in Korea has been currently growing every year, and as a result, approximately 0.2 million tons of Spent Coffee Grounds (SCG) are being created every year. SCG, which is waste organic material, is often classified as food waste and an annual amount of 0.27 million ton is discarded while containing moisture and provoking serious environmental issue. Physico-chemical characteristics of SCG were analyzed in this study and medium and long-term growth experiments were conducted in order to evaluate its utilization potential. According to the experiment results, mixing SCG into the previous base material resulted in accelerated germination and growth in the mid-term compared to previous base material alone, despite slower germination or growth in early stage. Especially, it showed lower withering rate and decrease in various symptoms that are caused by nutrition shortage in case of discontinued sprinkling, etc., compared to the previous base material. Hence, while SCG has a feature of hindering early development due to its feature of waste organic material that is rich in nitrogen, its benefit for long-term growth coming its moisturizing ability and supply of organic matter was confirmed in the study. On balance, SCG is believed to be a material that can replace or complement the previous base materials.

• Clinical and Experimental Pediatrics
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• v.53 no.1
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• pp.21-27
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• 2010

Purpose : In contrast with traditional time-cycled, pressure-limited ventilation, during volume-controlled ventilation, a nearly constant tidal volume is delivered with reducing volutrauma and the episodes of hypoxemia. The aim of this study was to compare the efficacy of pressure-regulated, volume controlled ventilation (PRVC) to Synchronized intermittent mandatory ventilation (SIMV) in VLBW infants with respiratory distress syndrome (RDS).Methods : 34 very low birth weight (VLBW) infants who had RDS were randomized to receive either PRVC or SIMV with surfactant administration : PRVC group (n=14) and SIMV group (n=20). We compared peak inspiratory pressure (PIP), duration of mechanical ventilation, and complications associated with ventilation, respectively with medical records. Results : There were no statistical differences in clinical characteristics between the groups. After surfactant administration, PIP was significantly lower during PRVC ventilation for 48hrs and accumulatevive value of decreased PIP was higher during PRVC ventilation for 24hrs (P<0.05). Duration of ventilation and incidence of complications was no significant difference. Conclusion : PRVC is the mode in which the smallest level of PIP required to deliver the preset tidal volume in VLBW infants with RDS, adaptively responding to compliance change in lung after surfactant replacement.