• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.577-584
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• 2018

This study was conducted to investigate the potential of chicken feather (CF), which is a by-product in poultry industry, as a partial substitute of wood fiber in the production of wood-based fiberboard. Keratin-type protein constituted the majority of CF, and its appearance did not differ from that of wood fiber. When the formaldehyde (HCHO) adsorptivities of CF compared by its pretreatment type, feather meal (FM), which was pretreated CF with high temperature and pressure and then grounded, showed the highest HCHO adsorptivity. In addition, there was no difference between the adsorbed HCHO amounts, which was measured by dinitrophenylhydrazine method, of scissors-chopped CF and CF beated with an electrical blender. Mechanical properties and HCHO emission of medium-density fiberboards (MDF), which were fabricated with wood fiber and 5 wt% CF, beated CF or FM based on the oven-dried weight of wood fiber, were not influenced by the pretreatment type of CF. However, when the values compared with those of MDF made with just wood fiber, thickness swelling and HCHO emission of the MDF were improved greatly with the addition of CF, beated CF or FM. Based on the results, it might be possible to produce MDF with improved dimensional stability and low HCHO emission if CF, beated CF or FM is added partially as a substitute of wood fiber in the manufacturing process of MDF produced with the conventional urea-formaldehyde resin of $E_1$ grade. However, the use of CF or FM in the production of MDF has a low economic feasibility at the current situation due to the securing difficulty and high cost of CF. In order to enhance the economic feasibility, it requires to use CF produced at small to medium-sized chicken meat plants. More importantly, it is considered that the technology developed from this research has a great potential to make provision for the prohibition of animal-based feed and to dispose environmentally avian influenza-infected poultry.

• Journal of Bio-Environment Control
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• v.27 no.3
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• pp.231-238
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• 2018

Chlorophyll fluorescence, chlorophyll content, graft-taking and growth of grafted cucumber seedlings as affected by photosynthetic photon flux (PPF) of LED lamps were analyzed in this study. Four PPF levels, namely 25, 50, 100, $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ were provided to investigate the effect of light intensity on the chlorophyll fluorescence, chlorophyll content, graft-taking and growth of grafted cucumber seedlings. Air temperature, relative humidity, and photoperiod for graft-taking were maintained at $25^{\circ}C$, 90%, $16h{\cdot}d^{-1}$, respectively. Maximum quantum yield (Fv/Fm) of rootstock as affected by PPF was found to be 0.84-0.85 and there was no significant change in Fv/Fm. Even though Fv/Fm of scion measured at 2 days after grafting was lowered to 0.81-0.82, after then it gradually increased with increasing PPF. At 4 days after grafting, the chlorophyll content extracted from scion increased with increasing PPF. Graft-taking ratio of grafted cucumber seedlings was 90-95% as PPF was ranged from $25{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ to $100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. However, the graft-taking ratio of grafted seedlings healed under PPF of $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ was decreased to 80%. Maximum PPF measured required for smooth joining of rootstock and scion was assumed to be $100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. At healing stage of grafted cucumber seedlings, Fv/Fm of scion decreased and at least two days after grafting were required for rooting of grafted seedlings. Chlorophyll fluorescence response of rootstock and scion was linked to light irradiation. Therefore, it was concluded that physical environment including light and humidity during healing process of grafted seedlings should be controlled more precisely to facilitate root formation and to prevent scion from lowering Fv/Fm. Further studies are required to investigate the effects of root development and joining of vascular bundles of grafted seedlings on the chlorophyll content of scion.

• Environmental Engineering Research
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• v.19 no.2
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• pp.123-130
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• 2014

Percolation is the important process of extracting the soluble constituents of a fine mesh, porous substance by passage of a liquid through it. In this study, bio-wastes were percolated under various conditions through continuous percolation processes, and the energy potential of percolate was evaluated. The representative bio-wastes from the K composting plant in Darmstadt, Germany were used as the sample for percolation. The central objective of this study was to determine the optimal amount of process water and the optimum duration of percolation through the bio-wastes. For economic reasons, the retention time of the percolation medium should be as long as necessary and as short as possible. For the percolation of the bio-wastes, the optimal percolation time was 2 hr and maximum percolation time was 4 hr. After 2 hr, more than two-thirds of the organic substances from the input material were percolated. In the first percolation process, the highest yields of organic substance were achieved. The best percolation of the bio-wastes was achieved when the process water of 2 L for the first percolation procedure and then the process water of 1.5 L for each further percolation procedure for a total 8 L for all five procedures were used on 1,000 g fresh bio-waste. The gas formation potentials of 0.83 and $0.96Nm^3/ton$ fresh matter (FM) were obtained based on the percolate from 1 hr percolation of 1,000 g bio-waste with the process water of 2 L according to the measurement of the gas formation in 21 days (GB21). This method can potentially contribute to reducing fossil fuel consumption and thus combating climate change.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.44
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• pp.297-309
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• 1997

Exceptional Elements(E.E) are generally eliminated by a machine duplication or a subcontract in cellular manufacturing system. One of the advantages in FMS consists of machines capable of multi-processing. This paper presents a method that eliminates E.Es by tool duplication. First, we develop the exceptional operation similarity(EOS) by machine cell-operation incidence matrix and part-operation incidence matrix. The EOS indicates a similarity of unperformable operations in each part when two exceptional parts are assigned to a machine cell. Secondly, a mathematical model to minimize tool duplication is developed by the EOS. Finally, a heuristic algorithm is developed to reflect dynamic situation in process of elimination of exceptional elements by the EOS and the mathematical model. A numerical example is provided to illustrate the algorithm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.765-768
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• 2002

This study focuses on designing a new gluing system for the FM-I (Freeform Master I), which is a new rapid prototyping machine using a sheet lamination technique. To design the system, we firstly verify the required parameters of the proposed gluing system. Then we analyze the electro-magnetic system by using ANSYS and the mechanical system by using numerical methods. The gluing system can contribute to reduce the cost of the machine since it can be applied to low cost materials such as a plain paper.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.89-92
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• 2005

This study investigates influence of particle properties of crushed sand on the duality of concrete. The test shows that an increase of fineness modulus(FM) resulted in high slump and air contents, while compressive strength decreased due to decreased adhesion with reduction of surface area. As grain shape become rounder, the slump of concrete increased, due to reduction of internal friction, and increased air contents. The reduction of adhesion by abrasion of surface declined compressive strength during the process of manufacturing crushed sand. Increase of powder contents decreased slump and it also decreased air contents due to the effect of filling air void. In addition. using powder contents increased compressive strength, but could not find any difference of bleeding and tensile strength with particle properties.

• Journal of Korean Institute of Industrial Engineers
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• v.20 no.2
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• pp.51-64
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• 1994

Cellular manufacturing requires formation of machine cells that can produce families of parts with similar processing requirement. The purpose of cell formation is to create separable machine clusters and part families simultaneously. However, the cell formation process often includes the identification of exceptional elements. This paper presents cell formation method under consideration of alternative routings in FMS which consists of machines capable of multi-processing and parts which require more than one operation. We suggest theorems to calculate the maximum number of machine cell and part family which have no exceptional elements. We also develop a cell formation algorithm which is based on the suggested theorem. A numerical example is provided to illustrate the proposed theorem and algorithm.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.10
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• pp.13-29
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• 1996

생산분야에 있어서의 기술혁신은 1980년대에 들어 급속적으로 확대되었으며 NC 공작기계와 Robot등의 기기와 Software 그리고 더 나아가서 통신 System과 연결되어 더욱 종합적인 고도의 생산 시스템이 개발, 구축 되어가고 있다. CIM(Computer integrated manufacturing)은 상기한 여거 시스템의 구성요소를 최대한으로 통합 화시킨 것이다. 다시 말하면, 기계 가공 중심의 Image를 가지고 있는 FMS와 가공, 조립의 종합적인 자동화를 추구하는 PA(Process Automation-처리과정의 자동화)와 제조에 관련된 OA(Office Automation)를 포함하게 된 것을 CIM이라고 생각하게 된 것이다. Computer에 의한 계측설계와 생산기술 그리고 더 나아가서 생산관리를 종합적으로 한 것이다. 그러한 의미로 볼 때, CIM은 가장 넓은 영역을 포함하는 생산개념이라고 말할 수 있다.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.1
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• pp.1-10
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• 2003

A recent trend In flexible manufacturing systems (FMS) Is to utilize the Identical versatile machines with fast tool delivery devices. Unlike a conventional FMS where parts are fed to the machines with the required tools, tools are acquired from other machines using a tool delivery system and parts can be finished on the same machine In these FMS. Therefore it Is more important problem 4o plan tool flow using tool delivery system In these FMS rather than part flow In conventional FMS. According to the existing study, In FMS 20∼30 percent of the total management cost Is the cost related with tools and It Is possible to reduce the tool Inventory by 40 percent using efficient tool allocation. In this study, In FMS under dynamic tool allocation strategy, a new method of part release considering tool flow at the stage of part release Is proposed. In order to prove the efficiency of the proposed part release It is compared with other part release through simulation experiments. Performance measures in these experiments are the throughput and the number of tardy parts.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.10
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• pp.2329-2338
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• 1997

A conventional digital receiver sampled a baseband signal and processed it digitally for demodulation. But now we can sample at sufficiently high speed a wideband signal to take enough discrete data values due to the advent of economic high-speed ADC. With this technical background, a wideband frequency-division-multiplexed signal can be undersampled and channelized in digital domain by DFT analysis filter using the theory of polyphase. In this paper, we propose a new digital receiver which can digitally process the multichannel received signal by sampling at IF band, develop a mathematical theory and algorithm, and analyze the performance by using C-language simulaation. The proposed receiver can demodulate analog and digital FM signals.