• Fire Science and Engineering
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• v.32 no.3
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• pp.134-139
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• 2018

Extremely fine particles seriously affect people and are becoming a social problem. Conventional methods using the type of beta ray absorption are difficult to have real-time measurements and miniaturization for the acquisition of fine dust. In this paper, a light scattering method was used. The sensors were configured internally with semiconductor laser diodes for miniaturization, low cost and lightweight. The use of the FFT method makes it easier to separate fine dust according to size compared to conventional light scattering sensors. Bluetooth communication also allows the connection, monitoring and control of devices using smart phones.

• Journal of ILASS-Korea
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• v.6 no.1
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• pp.35-43
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• 2001

Previous studies on image processing techniques for panicle size measurement usually have focused on a single panicle or weakly overlapped particles. In the present work, the image processing algorithm for particle size measurement has been improved to process heavily-overlapped spherical-particle images. The algorithm consists of two steps; detection of boundaries which separate the images of the overlapped panicles from the background and the panicle identification process. For the first step, Sobel operator (using gray-level gradient) and the thinning process was adopted, and compared with the gray-level thresholding method that has been widely adopted. In the second, Hough transform was used. Hough transform is the detection algorithm of parametric curves such as straight lines or circles which can be described by several parameters. To reduce the measurement error, the process of finding the true center was added. The improved algorithm was tested by processing an image frame which contains heavily overlapped spherical panicles. The results showed that both the performances of detecting the overlapped images and separating the panicle from them were improved.

• Journal of Energy Engineering
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• v.26 no.2
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• pp.73-79
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• 2017

In nucleation assisted crystallization process formed $CO_2$ leaves as colloid gas and is used as the template by the rapidly growing crystals in the nucleation site. This emulsion of $CaCO_3$ micro-crystals & $CO_2$ micro-bubbles forms hollow particles. Formed hollow particles are double walled, both internal and external faces belonging to the cleavage aragonites which separate the surrounding water from the enclosed gas cavity. Hence, the reverse reaction of $CO_2$ with water forming Carbonic Acid is not possible and the pH stability is maintained. In fact every excess $CaCO_3$ crystals are buffering any carbonic acid left over. This $CO_2$ based nucleation technology prevents scale formation in water channels, but it also helps to reduce the previously formed scales. This process takes out water dissolved $CO_2$ in almost-visible micro-bubbles forms that helps reducing previously formed scale over a period of time (depends on the usage period). The aragonite crystals can't form scale because of its stable molecular structure and neutral surface electro potentiality.

• Journal of Aquaculture
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• v.13 no.3
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• pp.223-230
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• 2000

A rearing experiment of the olive flounder was performed in a set of water-reuse system to test the reusability of the water in culture system with (i) a foam fractionator to separate particles from water and (ii) a culture tank contain mineral particles to filter the metabolic wastes by adsorption and/or decomposition. Two kinds of commercially processed loess particles and a dolomite particle (all 50 ${\mu}$diameter) were tested. The mineral particles were suspended in the culture tank and the water was pumped into the foam fractionator, where the particles were separated and drained out with foam from the system. In a circular culture tank of 4.8 m in diameter with 10 d water, the juvenile olive flounders (23.1 g/fish, 5,555 fish, 128 kg total body weight) were stocked. 90 % of the rearing water was reused and turnover rate of the water in the tank was two times per hour. Water temperature was maintained 17${\pm}$1$^{\circ}C$. At the end of 75 day-experimental rearing, 5,532 flounders, weighing 468 kg, were harvested. An individual flounder grew to 84.6 g of body weight. The final stocking density was 26.0 kg/$m^2$. No diseases were observed during the experiment.

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.179-190
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• 2003

The grout based on solution type makes it difficult to get the improvement of ground strength and the effefct of water curtain because it has lower strength and durability than suspension type. Nowadays, the technology of particle acceleration, that enhance the material permeability, such as grout based on solution type, and inexpensive grout, is being required. For these reasons, in this study, using wet milling system, we evaluated physical properties of manufactured factors such as water-cement ratio of particles before being milled, optimum milling capacity by controlling milling time and rpm, viscosity of materials, permeation coefficient, and unconfined compressive strength. Also, using micro wet milling apparatus which could manufacture ordinary Portland cement and high speed shear mix which could forcefully separate conglomerate particles in situ, we performed electrical resistivity investigation and falling head permeability tests to analyze differences of grouting effects. From these results, we found that the permeability of the applied equipment was much superior, and in the case of using high speed shear mixer, particles of grout material were well separated.

• Resources Recycling
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• v.10 no.3
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• pp.14-22
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• 2001

For the recycle of coal fly ash generated from power stations, we developed an electrocyclone system which can separate unburned carbon form coal fly ash, based on the fact that coarse fly ash particles contain higher amount of unburned carbon and unburned carbon particles are charged positively, and pure ash particles are charged negatively on contacting each other. Additionally, guide vanes were installed in the cyclone to control the cut size. Two types of electrode, stick and grid type, were designed to investigate the effect of electrode type. Results show that by introducing an electric field inside the cyclone, the yield increases by 5 to 15e1o. But the content of unburned carbon in the clean ash does not change significantly.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.3
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• pp.285-291
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• 2015

A centrifuge works on the principle that particles with different densities will separate at a rate proportional to the centrifugal force during high-speed rotation. Dense particles are quickly precipitated, and particles with relatively smaller densities are precipitated more slowly. A decanter-type centrifuge is used to remove, concentrate, and dehydrate sludge in a water treatment process. This is a core technology for measuring the sludge conveyance efficiency improvement. In this study, a smoothed particle hydro-dynamic analysis was performed for a decanter centrifuge used to convey sludge to evaluate the efficiency improvement. This analysis was applied to both the original centrifugal model and the design change model, which was a ball-plate rail model, to evaluate the sludge transfer efficiency.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.451-454
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• 2006

This paper presents an overview of ONP deinking efficiency with cellulolytic enzymes and synthetic collector in alkaline pH. Deinking is a series of unit operations designed to detach ink from cellulose fibers and separate the dispersed ink from the pulp slurry. Deinking chemicals are process aids that enable expensive mill equipment used in these unit operations to operate more efficiently - often much more efficiently. We propose the blended deinking agent with cellulolutic enzymes and synthetic collector in deinking pulp of conventional alkaline method. The deinking efficiency of old news print in alkaline pH was enhanced with enzyme treatments. The brightness of deinked pulp was increased with less residual ink particles and yield of enzymatic deinked pulp was improved compared to the deinked pulp of conventional alkaline method.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.11a
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• pp.9-14
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• 2006

Deinking is a series of unit operations designed to detach ink from cellulose fibers and separate the dispersed ink from the pulp slurry. Deinking chemicals are process aids that enable expensive mill equipment used in these unit operations to operate more efficiently. This paper presents an overview of ONP deinking efficiency with cellulolytic enzymes and synthetic collector in low alkalinity process. The deinking efficiency of old news print even in low alkalinity condition was enhanced with enzyme contained complex agent. The brightness of deinked pulp was increased with less residual ink particles and yield of deinked pulp was improved compared to the deinked pulp of conventional alkaline method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.5
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• pp.384-393
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• 1998

A mixed powder of electrolyte and matrix support materials with a proper proportion was used for the fabrication of an electrolyte matrix sheet. The purpose of this study is to reduce the large change in MCFC cell thickness occurring in the initial start-up period when separate sheets of electrolyte and support are used. A focus was put on how small the carbonate particles could be made. The particle size of the carbonate powder was controlled by ball milling and the distribution was measured using a particle size analyser. The thickness change was reduced to 20% by this approach, which could be compared to 27% observed in a conventional cell. The thickness changes of electrolyte matrix have linear relation sizes of carbonate powders.