• 한국지반공학회지:지반
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• 제14권1호
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• pp.81-92
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• 1998

화력발전소에서 대량으로 부산 되어 폐기 처리되고 있는 석탄회 폐기물로 조성된 지반을 안정 처리하여 사용하거나 또는 이러한 석탄회를 건설공사의 직접적인 재료로 활용하게 되면 결국 폐자원을 산업자원화 함으로서 건설자재 난을 해소할 수 있게 된다. 본 연구에서는 석탄회를 성토재 및 매립재로서 대량 활용할 경우와 지반변형해석에 필요한 적용 모델과 그 적용성을 중심으로 검토하였다. 그 중 Cam-clay model은 흙의 다양한 응력경로에 대해 배수와 비배수 조건에서 재하하는 동 안 변위와 공극수압을 나타낼 수 있는 완전한 구성식을 제공하고, 필요로 하는 토질정수가 극소수이고 모든 것을 실내실험을 통해 측정할 수 있는 장점이 있다. 토질기본시험, 등방압밀 및 비배수 삼축압축시험 등을 통하여 Camflay mode숙 제반 parameter를 구하였고, 수치해석을 수행하여 시험 결과와 비교하였다. 시험 결과와 수치 해석결과에서 각각 구한 parameter의 오차는 매우 근소 한 것으로 나타났다. 시험을 통해 결정한 비회와 저회 5 : 5 적정혼합회의 Parameter들은 인공으로 조성된 석탄회 매립지반의 변형해석에서 Cam-clay model을 이용하는 데에 기초자료로서 활용이 가능할 것으로 판단된다.

• Computers and Concrete
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• 제8권5호
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• pp.583-595
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• 2011

This paper studied the cement efficiency factor (k factor) of high calcium Class F fly ash. This k factor represents a unit of fly ash with efficiency equivalent to k unit of cement. The high calcium Class F fly ash was used to replace cement in concrete. The modified Bolomey's law with linear relationship was used for the analysis of the result of compressive strength, cement to water ratio (c/w) and fly ash to water ratio (f/w) by using the multi-linear regression to determine the k factor and other constants in the equations. The results of analysis were compared with the results from other researcher and showed that the k factor of high calcium Class F fly ash depends on the fineness of fly ash, replacement level and curing age. While the amount of CaO content in Class F fly ash not evident. Furthermore, necessary criteria and variables for the determination of the k factor including the use of the k factor in concrete mix design containing fly ash were proposed.

• 대한가정학회지
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• 제41권8호
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• pp.55-62
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• 2003

Natural dyes generally fan into two categories; organic dyes coming from animals and plants and inorganic dyes obtained from various minerals such as bengala, loess, ultramarine, prussian blue and etc. The main components of volcanic ash is clay mineral such as kaolinite, illite, quartz. Clay minerals Composing volcanic ash are kaolinite［$Al_4Si_4O_{10}{(OH)_{8}}$］, illite［$K_{X}Al_2(Si,\;Al)_4O_{10}{(OH)}_2$］, quartz［$SiO_2$］, homblende［$Na_{0-1}\;Ca_2{(Mg,\;Fe,\;Al)}_5{(Si,\;Al)}_{8}O_{22}{(OH)}_2$］and etc. And the redish color mainly comes from iron oxide. In this paper, two different classes of dyeing process were tested; dyeing with volcanic ash only and cationic agent pre-treatment followed by dyeing with volcanic ash. The compositions of the volcanic ash powder and the volcanic ash deposited on the cotton knitted fabrics identified by energy dispersive spectrometer and XRD analysis. The major chemical components of volcanic ash deposited on the cotton knitted fabrics were confirmed to be the saicon oxide, iron oxide, and aluminum oxide and etc. According to the analysis by XRD and EDS-SEM, kaolinite, illite and quartz were also identified.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1996년도 춘계학술발표회 초록집
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• pp.88-96
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• 1996

The characteristic analysis of fly ash generated from a fired power plant using bunker-C oil has been investigated. Ash size distribution by an optical microscopy with image processing technique, morphological shape by a scanning electron microscope(SEM) and microscope, chemical composition by the inductively coupled plasma emission spectrometry(ICP), and resistivity measurement as a function of temperature and moisture content by the resistivity meter are performed. A study of physical, chemical and electrical characteristics of bunker-C fly ash plays an important role of improving the performance of an electrostatic precipitator and protecting air pollution. The samples of bunker-C fly ash for analysis were collected from the electrostatic precipitator hopper of Ulsan Power Plant Unit 1 and Pusan Power Plant Unit 1. Mass median diameter(MMD) of bunker-C fly ash was measured 12.7${\mu}{\textrm}{m}$, while MMD of fly ash generated from the mixture of bunker-C oil(40%) and domestic anthracitic coal(60%) was 25.7${\mu}{\textrm}{m}$. The morphological structure of bunker-C fly ash consisted of fine particles of non-spherical shape. The primary chemical components of bunker-C fly ash were composed of SiO2(2.36%), Al2O3(4.91%), Fe2O3(14.33%) and C(11.84%). Resistivity of bunker-C fly ash was found to be increased with increasing temperature at the range of 100~15$0^{\circ}C$ and was measured 103~104 ohm-cm.

• KEPCO Journal on Electric Power and Energy
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• 제8권2호
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• pp.97-101
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• 2022

In this study we investigated the gas to solid heat transfer of bubbling fluidized bed bottom ash cooler installed at the Donghae power plant in South Korea. Several different analyses are done through 1-D calculations and 3-D CFD simulation to predict the bottom ash exit temperatures when it exits the ash cooler. Three different cases are set up to have consideration of unburnt carbon in the bottom ash. Sensible heat comparison and heat transfer calculation between the fluidization air and the bottom ash are conducted and 3-D CFD analysis is done on three cases. We have obtained the results that the bottom ash with unburnt carbon is exiting the ash cooler, exceeding the targeted temperature from both 1-D calculation and 3-D CFD simulation.

• Bulletin of the Korean Chemical Society
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• 제35권1호
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• pp.69-75
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• 2014

Accurate analysis of fly ash particles is not trivial because of complex nature in physical and chemical properties. SPLITT fractionation (SF) was employed to fractionate the fly ash particles into subpopulations in large quantities. Then the SF-fractions were analyzed by the steric mode of sedimentation field-flow fractionation (Sd/StFFF) for size analysis. The SF-fractions were also analyzed by ICP-OES. The results showed that the fly ash is mainly composed of Fe, Ca, Mg and Mn. No particular trends were observed between the particle size and the concentrations of Fe, Ca, Mg, while Mn, Cu and Zn were in higher concentrations in smaller particles. Sample preparation procedures were established, where the fly ash particles were sieved to remove large contaminants, and then washed with acetone to remove organics on the surface of particles. The sample preparation and analysis methods developed in this study could be applied to other environmental particles.

• 한국농공학회논문집
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• 제55권2호
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• pp.77-85
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• 2013

The aim of this study is to investigate strength and water purification characteristics of effective microorganism-applied volcanic ash block using flexural strength test and water quality analysis. The specimens were prepared with volcanic ash from Mt. Baekdusan and Mt. Hallasan, and cement as the ratios of 3.5:1, 4.0:1, 4.5:1, 5.0:1 with and without metakaolin. Flexural strength degraded with increasing of the amount of volcanic ash, and increased with addition of metakaolin as a binder. Based on these results, the optimal ratio for fabricating volcanic ash-cement mixture block is determined as 3.5:1 with metakaolin. Furthermore, from water quality analysis on contaminated water, removal ability of effective microorganism-applied volcanic ash-cement mixture block and caged volcanic ash block against T-N, T-P and SS was highly evaluated because of adsorption due to the large specific surface area of volcanic ash. Hence, volcanic ash-cement mixture block and caged volcanic ash block possibly contribute to water purification.

• 자원리싸이클링
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• 제13권5호
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• pp.51-56
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• 2004

국내 석탄화력발전에서 발생되는 바닥재 재활용의 경제성을 평가하고자 신설 500 MW${\times}$2기 유연탄 화력발전설비를 대상으로 바닥재 재활용이 가능한 건식처리시스템 도입의 경제성을 충수중력식 습식처리시스템과 비교하여 검토하였다. 신규발전설비에 건식처리시스템 도입 시 시설투자비는 습식처리시스템의 약 150% 수준으로 초기투자비는 더 소요되나, 바닥재 재활용을 통한 판매이익을 고려한 연간시설운영비는 습식처리시스템의 약 17%까지 절감되는 것으로 예측하였다. 이를 기초로 경제성 분석을 수행한 결과 건식처리시스템 도입 시 추가로 소요되는 초기투자비는 4.8년에 회수가 가능하며 투자이익률은 21.1%로 평가되었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.344-347
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• 2004

The amount of coal ash has been increasing and development of effective use is urgently needed. Various by-products and waste are expected to be used as resources from the point of reduction in environmental load. This is an experimental study to compare the properties of high volume coal ash concrete using the reclaimed coal ash. For this purpose, authors have started work to develop a production method of hardening coal ash concrete. Laboratory tests show that the optimum mixture of coal ash concrete can be determined from multiple regression analysis. According to test results, it was found that the compressive strength of the concrete can be determined by a single curve. And it is obtained from the analysis of the results tested for concrete with the ratio of total power to water and amount of land reclamation ash.

• 한국농공학회논문집
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• 제46권5호
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• pp.99-106
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• 2004

Although fly ash has possesses viable engineering properties, an overwhelming majority of fly ash from coal combustion is still placed in storage or disposal sites. This study was undertaken to investigate the physical and mechanical properties of clay-fly ash mixture and to furnish engineering data when fly ash utilized as engineering materials. This paper includes geotechnical properties of fly ash, clay-fly ash mixtures and results of compaction test, unconfined strength test, direct shear test, leaching test and stability analysis of clay-fly ash bank slope. If proper amount of fly ash was put in clay, the clay-fly ash mixture has an increase of unconfined strength and stability of bank slope.