• Journal of Wetlands Research
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• v.14 no.4
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• pp.471-478
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• 2012

The objective of the study is to find a way to utilize MSWI slag as filter material and to verify it. To do so, stability as filter material was tested, and used Ju-Munjin filter sand as control group to run actual filtering experiment to analyze filtering efficiency. According to result, MSWI slag is usable within designated waste acceptable standards. Also, it showed similar level of filtering capability to filter sand. Thus, MSWI slag could help to save and recycle resources if used as filtering material instead of filter sand As result of filtering test, SS and COD showed about same level of filtering capability similar to standard filter sand. MSWI slag has shown 26.96% higher with T-N, and 6.55% higher with T-P compared to standard filter sand. Also, remove efficiency comparison result with No. 40#(0.43mm) and mixed diameter showed equal or greater filtering capability.

• Journal of the Korean Geosynthetics Society
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• v.17 no.1
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• pp.1-10
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• 2018

We conducted research to develop a solidification agent for the ground surface reinforcement method in which activator is fused by recycling pig iron slag, which is a byproduct generated in the steel making process. The purpose of this research is to solve the problems of surface soil by improving the strength and durability of foundation soil such as soil loss, settlement, sinkhole, etc. by recycling pig iron slag from disused or landfilled steelworks. For this purpose, the possibility of using pig iron slag as a solidification soil was evaluated by the compressive strength, elution test of harmful materials, permeability coefficient test. As a result of the compressive strength test, the values of the strength of the curing 28 days of the solidified soil having the solidification agent mixing ratio of 12% were found to be 0.93, 0.96 and 1.3 MPa, respectively, satisfying the required strength value of 1 MPa, In the case of permeability coefficients, the minimum values were $4.1{\times}10^{-8}$, $7.0{\times}10^{-7}$, and $1.7{\times}10^{-7}cm/sec$, respectively, at the solidification agent mixing rate of 12%. In addition, as a result of the elution test of harmful materials, a small amount was detected in the item of hexavalent chromium but satisfied the inclusion criteria, and in the remaining items, heavy metals were not eluted.

• Journal of the Korean Geotechnical Society
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• v.19 no.2
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• pp.159-170
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• 2003

In this study, the mixed design of grout with hish strength.high permeation.high durability and environmental stability as the state of the art in material field was performed. Also, the subjects of grouting, grouting effects for ground conditions, and environmental effects were analyzed. According to these results, the fundamental data will be suggested as a design of grouting in the field application. The physical, mechanical and chemical characteristics with particle shape of the grouts were analyzed. Then, the gel-time of grouts, which is essential for workability and permeation range, were controlled. Also, the laboratory model grouting tests were performed to find the characteristics of solidification, permeation and durability with grouts. The ordinary portland, slag and microcement which have been used in the construction field were evaluated fur the environmental effects. To find the leaching of $Cr^{6+}$characteristics in cement grouts, $Cr^{6+}$ leaching tests were performed for the raw materials. Also, the results of leaching test were shorn by surrounding environment. Then, the unconfined compression strength tests were performed with the homo-gel samples, and the amount of changed $Cr^{6+}$ was measured by curing solution.

• Journal of Conservation Science
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• v.36 no.2
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• pp.103-111
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• 2020

To compare the cleaning effect of solvents such as water and ethanol used to clean lacquer relics, the components extracted with various solvents were analyzed. A freshly dried lacquer sample and a lacquer sample exposed to ultraviolet radiation for 24 days were treated with water, ethanol, acetone, and hexane, and the dissolved material was detected by pyrolysis-gas chromatography-mass spectrometry. The amount extracted was significantly higher in acetone and ethanol than in hexane, a nonpolar solvent. Water, a highly polar solvent, was relatively efficient for extracting low-molecular-weight materials. After experiencing 24 days of ultraviolet radiation, the lacquer exhibited a significant increase of extracted materials compared with the nonexposed one. This may be due to the degradation of the urushiol chain in the form of polymers, resulting in the formation of low-molecular-weight polar substances, including dicarboxylic acids. In addition to the deterioration status of lacquer relics, such solvent extraction properties will be a crucial consideration in selecting the appropriate cleaning solvent.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.118-118
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• 2003

편의와 fresh-like quality를 선호하는 소비 경향에 맞추어 가공한 fresh-cut사과의 선도 연장을 위한 저해제를 탐색하였다. 실험에 사용된 사과는 박피하여 속심을 제거한 사과를 8조각으로 절단하여 저해제에 3분간 침지한 후 물기를 제거하고 각각 LDPE 포장지에 포장하여 실온에서 저장하면서 colorimeter와 rheometer를 이용하여 색도와 물성을 측정하였다. 저해제로는 1% ascorbic acid, citric acid, NaCl, MgCl$_2$, CaCl$_2$, KCl, CaSO$_4$, MgSO$_4$, $Na_2$SO$_4$, oxalic acid, calcium lactate, calcium citrate를 사용하였으며 천연저해제로는 건칡, 맥문동, 목향, Rhubarb, 당귀, 오약, 시체, 지각, 천문동, 청피, 계피, 구기자, 당귀, 진피, 감초, 녹차, 후추 등을 열수추출하여 사용하였다. 물리적인 변화는 시간이 경과함에 따라 감소하는 추세를 보였으며 일부 건조로 인해 texture의 증가를 나타내기도 했다. 처리에 따른 물리적인 변화로는 CaCl$_2$, NaSO$_4$, Cl, 시금치를 처리하였을 때 그 변화가 가장 작았으나 시금치의 경우 시금치로 인한 사과의 색변화로 관능적으로 좋지 않았다. 한약재는 목향, 당귀, 지각, 계피를 처리하였을 때 물리적인 변화가 가장 작았으나 시금치와 마찬가지로 처리 초기에 한약재 자체의 향과 색으로 인하여 관능적으로 좋지 못한 결과를 나타냈다. 갈변 정도를 나타내는 ΔE의 변화는 KCl과 CaCl$_2$, CaSO$_4$를 처리한 구에서 변화가 가장 작았으며 한약재를 처리하였을 경우 당귀, 천문동을 처리한 구에서 효과를 보였다. oxalic acid는 갈변저해에는 효과적이었으나 시간이 경과함에 따라 수분의 용출이 증가하였으며 물성의 변화도 컸다. 또한 ZnCl$_2$를 처리한 구에서는 이취 발생과 수분 용출이 컸으며 색의 변화도 컸다.

• Resources Recycling
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• v.16 no.2 s.76
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• pp.32-39
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• 2007

The measurement of physicochemical properties of ASR incineration ash has been carried dot and the preparation of light-weight material has also been performed using ASR ash for recycling point of view as building or construction materials. For this aim, chemical composition, particle size distribution, and heavy metal leachability were examined for 2 bottom ashes and 4 fly ashes obtained from the domestic ASR incinerator. In the present work, attempt has been made to prepare the lightweight material using boiler ash as a raw material, which is prepared by forming the mixture of boiler ash, lightweisht filler and inorganic binder and followed by calcination at elevated temperature. As a result, the content of Cu in bottom ash was as high as about 3wt% so that the recovery of Cu from ash was required. The major compound of SDR #5 and Bag filter #6 was found to be $CaCl_2{\cdot}Ca(OH)_2{\cdot}H_2O\;and\;CaCl_2{\cdot}4H_2O$, respectively. It is thought that heavy metal teachability of lightweight material prepared with boiler ash was significantly decreased due to the encapsulation or stabilization of heavy metal compounds.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.31 no.9
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• pp.16-23
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• 2002

현재 우리나라는 1980년대 후반부터 도시폐기물 소각시설을 설치하기 시작하여 전국적으로 20 여곳의 대형 소각장이 가동되고 있으며 대기오염 방지 기술도 발전에 발전을 거듭하여 불과 10 여년 동안에 선진국 수준의 대기오염 배출기준을 만족하는데 아무 문제가 없을 정도로 되었다. 그러나 소각후 발생 하는 소각재의 경우 비산재는 고형화등의 처리 후 매립하고 바닥재는 별도 처리없이 매립하는 실정이어서 매립 후 시간이 흐를수록 매립된 소각재에서 용출되는 다이옥신과 소각재 중에 포함된 중금속 등에 의한 토양오염과 수질오염의 우려가 남아 있는 것이 사실이다. 소각후 남는 소각재는 폐기물량의 약 15 %, 비산재는 약 1.5 % 정도 발생하는 것으로 볼 때 매립은, 특히 다음 세대에 유산으로 남겨진다는 점에서 더 이상 적절하지 않은 해결책으로 생각되며 유럽과 일본 등 선진국에서는 이미 이와 같은 소각재에 대한 무해화 처리기술이 개발되고 속속 상용화되고 있으므로 우리나라도 하루빨리 열분해용융시설등 신기술을 개발하거나 도입하여 세계적 환경 기술경쟁 에서 선진국과 어깨를 나란히 함은 물론 청정한 국토를 후손에게 물려줄 수 있도록 하는 대책이 강구되어 야 할 것이다. 본 고에서는 폐기물 처리기술의 세계 적 동향을 살펴보고 폐기물의 완전 자원화에 성공한 대우 써모셀렉트 열분해용융 기술의 특성에 대해 소개하고자 한다.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.11
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• pp.781-790
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• 2014

Contaminants such as organic matters, nutrients and toxic chemicals in rivers and lakes with a weak flow rate are first removed from the water and accumulated in the sediments. Subsequently, they are released into the water column again, posing direct/indirect adverse effects on the water quality and aquatic ecosystems. In particular, phosphorus is known to accelerate the eutrophication phenomenon when it is released into the water column via physical disturbance and biological/chemical actions as one of important materials that determine the primary production of aquatic ecosystems and an element that is stored mainly in the sediments in the process of material circulation in the body of water. In this study, the effect on reducing phosphorus release in sediments was analyzed by applying different capping materials to lake water, where the effect of aquatic microorganisms is taken into account, and to distilled water, where the effect of microorganisms is excluded. The experimental results showed that capping with chemical materials such as Fe-gypsum and $SiO_2$-gypsum further reduced the phosphorus release by at least 40% compared to the control case. Composite materials like granule gypsum+Sand showed over 50% phosphorus release reduction effect. Therefore, it is determined that capping with chemical materials such as granule-gypsum and eco-friendly materials such as sand is effective in reducing phosphorus release. The changes in phosphorus properties in the sediments before and after capping treatment showed that gypsum input helped to change the phosphorus that is present in lake sediments into apatite-P, a stable form that makes phosphorus release difficult. Based on the above results, it is expected that the application of capping technology will contribute to improving the efficiency of reducing phosphorus release that occurs in river and lake sediments.

• Journal of radiological science and technology
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• v.33 no.1
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• pp.37-44
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• 2010

We sought to confirm an independent factor about in-stent restenosis (ISR) in the patients who underwent drug-eluting stent (DES) and know a possibility as a predictor of measured coronary artery calcium score by MDCT. A total of 178 patients (159 men, $61.7{\pm}10.0$ years of age) with 190 coronary artery lesions were included in this study out of 1,131 patients who underwent percutaneous coronary intervention (PCI) with DES implantation for significant stenosis on MDCT at Chonnam National University Hospital between May 2006 and May 2009. All lesions were divided into two groups with the presence of ISR : group I (re ISR, N = 57) and group II (no ISR, N = 133). Compared to group II, group I was more likely to be older ($65.8{\pm}9.0$ vs. $60.2{\pm}9.9$ years, p = 0.0001), diabetic (21.8% vs. 52.6%, p = 0.0001), have old myocardial infarction (8.8% vs. 2.3%, p = 0.040), left main stem disease (5.3% vs. 0.8%, p = 0.047), and smaller stent size ($3.1{\pm}0.3\;mm$ vs. $3.3{\pm}0.4\;mm$, p = 0.004). Group II was more likely to be smokers (19.3% vs. 42.1%, p = 0.003), have dyslipidemia (8.8% vs. 23.3%, p = 0.019). Left ventricular ejection fraction, lesion complexity, and stent length were not different between the two groups. Total CAC score was $389.3{\pm}458.3$ in group I and $371.2{\pm}500.8$ in group II (p = 0.185). No statistical difference was observed between the groups in CAC score in the culprit vessel, left main stem, left anterior descending artery, left circumflex artery, and right coronary artery. On multivariate logistic regression analysis, left main stem disease (OR = 168.0, 95% CI = 7.83-3,604.3, p = 0.001), male sex (OR = 36.5, 95% CI = 5.89-2,226.9, p = 0.0001), and the presence of diabetes (OR = 2.62, 95% CI = 1.071-6.450, p = 0.035) were independent predictors of ISR after DES implantation. In patients who underwent DES implantation for significant coronary stenosis on MDCT, ISR was associated with left main stem disease, male sex, and the presence of diabetes. However, CAC score by MDCT was not a predictor of ISR in this study population.

• Resources Recycling
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• v.11 no.4
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• pp.27-36
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• 2002

The clinker of which main component was calcium-chloroaluminate ($l1CaOㆍ7Al_2$$O_3$ㆍ$CaCl_2$), was synthesized with the bottom ash of municipal solid waste incinerator ash. The hydration mechanism and synthesis temperature of calcium-chloro-aluminate were investigated. The synthesized clinker was blended with a cement. It was substituted with 3～13 wt.% for clinker and $CaSO_4$ of ordinary portland cement. The compressive strength and the content of leached heavy metals of its mortar were measured. Calcium-chloroaluminate was synthesized above $800^{\circ}C$ and its main hydrate was ettringite ($3CaOㆍAl_2$$O_3$ㆍ$3CaSO_4$ㆍ$32H_2$O). The calcium-chloroaluminate was also synthesized above $800^{\circ}C$ with the bottom ash of which size fraction was below 30 mesh mainly. The compressive strength of the blended cement mortar was increased as the additive content of the clinker synthesized from the bottom ash was increased by 11 wt.%. The concentration of heavy metals leached from each mortar was satisfied with the value of the environmental standards and regulations.