• Journal of the Korea Concrete Institute
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• v.26 no.3
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• pp.323-329
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• 2014

It is known that the best way to recycle fly ash is to use in concrete. It is impossible to bury in the ground this fly ash recently, so it is trying to use high volume fly ash concrete. Nevertheless, recent main research topics are focused in the part of material only, however, it is necessary to perform the researches about elasticity modulus, stress-strain relationship and structural behavior. Therefore, in this paper, 18 test members were manufactured with 3 test variables, namely fly ash replacement ratio 0, 35, 50%, concrete compressive strength 20, 40, 60 MPa and 2 tensile steel ratio. 18 test members were tested for flexural behavior. From the test results, there were no differences between 35, 50% high volume fly ash cement concrete and ordinary concrete without fly ash(FA=0%).

• Journal of the Korean Geotechnical Society
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• v.27 no.6
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• pp.81-95
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• 2011

This study investigates relative density test of standard sand and bottom ash which were devided into No.40, No.60, No.100, No.200 and resonant column tests were conducted for samples with the relative density of 40%, 55%, and 70% on the basis of the test results. Resonant column tests were also conducted for each residual bottom ash which contains the passing sample of No.200 with the relative density of 55%. By compressing each residual sample with the compaction energy of A-compact mold test, the passing percentage of No.200 sieve increased up to 30%, which led to the adjustment of relative density to 10%, 20%, and 30%. Test results show that maximum shear modulus and damping ratio of bottom ash are smaller than those of standard sand because crushing strength and unit weight of the former are smaller than those of the latter.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.1
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• pp.73-86
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• 2020

The materials generating from volcanic eruption are volcanic gases, lavas and pyroclastic materials. Volcanic ash which has small-grain size (< 2 mm in diameter) can be moved easily and disperse widely, thus it may affect to communities across hundreds of square kilometers. The impacts from volcanic ash fall on people, structures, equipments, plants and livestock largely depend on ash thickness. According to increasing ash thickness, the intensity and area of damage may increase and affect significant damages not to human health but also to infrastructures. To reduce the impacts from volcanic ash fall, we have to establish the guidances about the nature and extent of the hazard and prepare the actions to increase abilities of communities to manage hazard. Although we don't have any experience caused by volcanic ash fall during and after volcanic eruption, we need to prepare the impacts of volcanic ash fall for future eruption in the areas surrounding Korea.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.338-341
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• 2004

This study was carried out to understand the geochemistry of saline water circulating in an ash disposal pond of Seocheon power plant, Korea. For this study, ash pond waters, slurry water and seawater samples were collected and analyzed for major ions and trace elements. Results show that ash pond waters and slurry water are alkaline in nature due to high calcium content, and have high concentration of Ca, B, Li, As, Ba, Al, Si and Mn over seawater, suggest that these elements leached from fly ash even at high alkaline condition and ionic strength. Slurry water has high concentration of B, Ba, Li, Mn, Si and Sr compare to ash pond waters, expresses that these elements seem to be easily reached at initial stage fly ash-water interaction, and also might be associated with the surface of the fly ash particles. Additionally, PHREEQC program predicted several secondary solid phases, which are also influenced in the leaching of elements in to the saline water.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.4
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• pp.83-90
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• 2019

In this study, the characteristics of the SRF (Solid Refuse Fuel) prepared by blending each of the additives (citrus peel, waste wood, coal) in the heavy oil fly ash, evaluating the heavy oil fly ash recyclability. Recycling SRFs were fabricated by pellet extruding method after blending the heavy oil fly ash and additives based on 30% moisture content. As a result, the formability of the SRFs was excellent under condition of blending heavy oil fly ash with coal or citrus peel and the highest calorific value was 4,274 kcal/kg at heavy oil fly ash mixed with coal. Therefore, the formability and calorific value were improved when the heavy oil fly ash was mixed with coal(20 wt%) at 30% moisture content. From these results, the applicability of SRFs with additives was confirmed by using the heavy oil fly ash from J thermal power plant.

• Journal of Biosystems Engineering
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• v.25 no.1
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• pp.39-46
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• 2000

This work was conducted to study the operating characteristics of a grinding system designed to obtain fine rice husk ash powder. To find better utilizing of rice husk, a valuable by-product from rice production, once the rice husk was incinerated and the thermal energy was recovered from the furnace, the ash was fed and pulverized in the grinding system resulting a fine powder to be used as a supplementary adding material to the portland cement manufacturing . The rice husk ash grinding system consisted of a high speed centrifugal fan for the preliminary coarse milling and a dry-type stirred ball mill for the subsequent fine grinding . Total grinding time 9 5, 15, 30, 45 min), impeller speed (250, 500, 750 rpm) , and mixed ratio (4.8, 7.9, 14.9) were three operating factors examined for the performance of a stirred ball mill used for the fine grinding of ash. With the stirred ball mill used in this study, the minimum attianable mean diameter of rice husk ash powder appeared to be 2 ${\mu}{\textrm}{m}$. During the find grinding, the difference in specific surface area of powder showed an increase and the grinding energy efficiency decreased with the increase in total grinding time, impeller speed ,and mixed ratio. For the operating conditions employed , the resulting mean diameter of fine ash powder, specific energy input, and grinding energy efficiency were in the range of 1.79 --16.04${\mu}{\textrm}{m}$, 0.072-5.226kWh/kg, an d1.11-12.15$m^2$/Wh, respectively. Grinding time of 30 min , impeller speed of 750 rpm, and mixed ratio of 4.8 were chosen as the best operating conditions of the stirred ball mill for fine grinding . At these conditions, mean particle diameter of the fine ash, grinding energy efficiency, grinding throughtput, and specific energy input were 2.73${\mu}{\textrm}{m}$, 3.95$m^2$/Wh, 0.25kg/h, and 1.22kWh/kg, respectively.

• International Journal of Industrial Entomology and Biomaterials
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• v.13 no.2
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• pp.97-101
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• 2006

The efficacy of wood ash from Terminalia arjuna (arjun) and T. tomentosa (asan) has been tested against virosis of tasar silkworm, Antheraea. mylitta D. The Polyhedral Occlusion Bodies (POBs) of Cytoplasmic Polyhedrosis Virus of A. mylitta (AmCPV) were exposed to the aqueous solution (0.5 to 4%) of wood ash for 5 to 30 minutes. The treated suspension of POBs was orally inoculated once to tasar silkworm larvae after 24 hours of $1^{st}$ moult, and larvae reared in indoor on arjun leaves till spinning. The application of aqueous solution of wood ash has established its potential as antiviral agent against cytoplasmic polyhedrosis virus. Two percent aqueous solution of wood ash from arjun and asan dissolved the Polyhedral Occlusion Bodies (POBs) of cytoplasmic polyhedrosis virus of tasar silkworm and inactivated the virions within a short period of 20 to 30 minutes. In vivo efficacy of aqueous solution of wood ash resulted in reduction of larval mortality due to virosis. The mortality was reduced to $2.56{\pm}0.21\;and\;3.03{\pm}0.32%$ when treatment of 2.0% solution of wood ash of arjun and asan respectively were applied for 20 minutes, compared to inoculated control $(92.18{\pm}7.52%)$. No mortality was recorded when treatment of 2.5% solution of wood ash of arjun and asan were applied for 10 minutes or more.

• Journal of Energy Engineering
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• v.26 no.4
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• pp.45-56
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• 2017

Coal power plants produce electricity for the nation's power grid, but they also produce more hazardous air emissions than any other industrial pollution sources. The quantity is staggering, over 386,000 tons of 84 separate hazardous air pollutants spew from over 400 plants in 46 states. In South Korea also, annual coal ash generation from coal-fired power plants were about 6 million tons in 2015. Pollutants containing particulate matter 10, 2.5 (PM10, PM2.5), heavy metals and dioxins from coal-fired power plant. The emissions threaten the health of people who live near these power plants, as well as those who live hundreds of miles away. These pollutants that have long-term impacts on the environment because they accumulate in soil, water and animals. The present study is to investigate the physical and chemical characteristics of coal-fired power plant fly ash and bottom ash contains particulate matter, whose particulate sizes are lower than $PM_{10}$ and $PM_{2.5}$ and heavy metals. There are wide commercial technologies were available for monitoring the PM 2.5 and ultra-fine particles, among those carbonation technology is a good tool for stabilizing the alkaline waste materials. We collected the coal ash samples from different coal power plants and the chemical composition of coal fly ash was characterized by XRF. In the present laboratory research approach reveals that potential application of carbonation technology for particulate matter $PM_{10}$, $PM_{2.5}$ and stabilization of heavy metals. The significance of this emerging carbonation technology was improving the chemical and physical properties of fly ash and bottom ash samples can facilitate wide re use in construction applications.

• The Journal of the Petrological Society of Korea
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• v.27 no.1
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• pp.17-24
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• 2018

The volcanic history of the volcanic ash cloud movement recorded in the annals of the Choson dynasty in 1654, presumably due to explosive eruptions from Mt. Baekdu volcano. On October 21, 1654, volcanic ash and volcanic gas erupted from Mt. Baekdu could be interpreted as volcanic ash, which was transported to low altitude by winds of north and northeast winds and descended to the south of the peninsula along with volcanic ash clouds. The affected area appeared northward in the southern boundary of Hamgyeongdo, which is estimated to have moved the volcanic ash from Mt. Baekdu to the south of the Korean peninsula. Clouds of volcanic ash have passed through Jeokseong and Jangdan area, Gyeonggido about 500 km away from Mt. Baekdu. This is interpreted as a result of the formation of a volcanic ash cloud along the ground in a curved shape due to the influence of the prevailing wind, which was formed by Plinian-type eruption at Mt. Baekdu. This is reproduced by numerical simulations on the similar weather pattern model.

• Magazine of the Korea Concrete Institute
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• v.5 no.4
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• pp.156-166
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• 1993

The results of an experimental study on the manufacture and the mechanical properties of steel fiber reinforced polyester resin composites utilizing industrial waste products(fly ash) are presented in this paper. The composites using steel fiber, fly ash, unsaturated polyester resin, styrene monomer, catalyst (cobalt octate) and accelerator(methyl ethyl ketone peroxide), fine and coarse aggreates were prepared using various mixing conditions. As the test results show. the mechanical and physical properties, such as the compressive, tensile and flexural strengths, and the setting shrinkage of fly ash$\cdot$polyester resin composites were improved considerably by increasing the fly ash-binder ratio. And the workability of steel fiber reinforced fly ash$\cdot$polyester resin composites was reduced with increasing the fly ash-binder ratio and steel fiber content. Also, the compressive, flexural strength and toughness of the composites were remarkably increased by increasing steel fiber content.