• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.5
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• pp.512-517
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• 2014

This paper describes the development of new sweeping machine based on Cyclone Technology, which maintains constant suction power and uses it in a industrial applications as a method for dust removed from grinding work. The performance of a cyclone separator is determined by the turbulence characteristics and particle-particle interaction. To achieve this goal, we design cyclone technology based dust separator for sweeping machine has been proposed as a system which is suitable to work utilizing dust suction alternative to conventional manual system. and Numerical analysis with computational fluid dynamics(CFD) was carried out to investigate the working fluid that flow into cyclone dust separator in order to design optimal structure of the sweeping machine. The validation of cyclone model with CFD is carried out by comparing with experimental results.

• Journal of the Korea Institute of Building Construction
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• v.10 no.6
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• pp.19-26
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• 2010

Advanced construction technologies have been rarely applied to practical construction operations on jobsites due to a lack of quantified evaluation data of the performance of such technologies. The basic objective of this study is to suggest a feasible way for the evaluation of the performance of new technologies based on construction simulation techniques, which have been frequently used in academic research for productivity estimation. Steel staircase systems were selected as the new technology to be investigated. The simulation was implemented in various ways, such as one staircase to six staircases on a floor. The simulation results provided in this study suggest that planners are able to make a fundamental decision on the use of targeted new technology with the estimated performance data (productivity and unit costs). These findings also indicate that a simulation technique could be one of the methods appropriate for use as a planner's decision-making tool.

• Journal of Energy Engineering
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• v.9 no.3
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• pp.250-260
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• 2000

유동층 연소기술은 다양한 연료의 사용과 SOx와 같은 공해물질의 배출제어가 용이하여 환경규제에 대한 대처능력이 우수한 발전방식으로 널리 적용되고 있는 추세이다. 국내에서도 동해화력 1,2호기(200MWe급)가 유동층 연소방식을 도입하여 운전중에 있으며, 국내 무연탄을 연료로 사용하는 최대 규모의 순환 유동층 보일러라 할 수 있다. 본 논문에서는 IEA-CFBC 모델을 이용하여 개발된 동해화력 순환유동층 성능모사 시뮬레이션 틀을 이용하여 여러 가지 운전변수 변화에 따른 성능예측을 수행하였으며, 특히, 연소로의 성능향상을 위한 방안의 일환으로 사이클론 개조를 수행하고 그에 따른 성능모사를 고찰하였다. 본 성능평가 결과 연소로내 전체 차압을 증가시키는 운전을 지향하는 것이 연소로내 희박상의 온도분포를 낮추고, 탈황효율을 증가시켜 운전 안정화에 기여하는 것으로 나타났다. 또한, 본 시뮬레이션 틀을 이용한 운전변수 변화에 대한 성능예측 결과 동해화력 운전 실측치와 잘 일치하는 것으로 고찰되었다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.115-117
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• 2012

Task based modeling is essential in a construction operation simulation modeling. It allows dealing with local variables or delay factors that affect productivity and improves the reusability of existing operation models. An operation model can secure reality only if it reflects the real construction processes by effectively dealing with zoning issue. However, system users have some difficulties in modeling a construction operation that is consisted of several processes having different production units. Zoning is a major modeling issue when the task based modeling method is implemented using the existing discrete event simulation systems. This paper highlights the difficulty and presents a new method that complements the zoning issues attributed to different production units. The method is described in detail by presenting the flow of entities. It is confirmed that the zoning method effectively deals with the unbalance of production units between processes and facilitates to model an operation model having processes with different production units. The "Zoning module" contributes to increasing accuracy of simulation result.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.5
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• pp.420-427
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• 2016

The marine equipment companies expanding facility investment in accordance with the booming economy are suffering from the reduced demand and the growth of chinese businesses. In this regard, the risk of overinvestment and the importance of prudent equipment investment must be reconsidered. Thus, in this study we performed a productivity and economical efficiency analysis in order to evaluate the investment value on production facilities in a company under the present conditions. The freezer of a fishing vessel manufactured by N company is selected as the subject of our study, while the assembly and welding cooling plates are configured as the scope of automation. Analysis on productivity and economical efficiency was conducted through CYCLONE (Cyclic Operation Network) simulation and economic analysis methods after analyzing the production process of freezer. The proposed analytical technique can be used to support the investment decision in production automation equipment of fishing vessels freezer.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.341-343
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• 2012

This study introduces a method for computation of process and operation gap in the specific construction operation(i.e., RC frame construction applying a block-grouping scheme) using CYCLONE-based simulation modeling and analysis technique. Since uncertainty of construction environment exists, a thoughtful production planning is required to effectively deal with a risk resulting in schedule delay in advance. This study presents the concepts of a time delay occurred in a process level and operation level in a operation model, and a method of measuring gap-times in each level while the simulation progresses. It helps a site manager to decide how many segmentation in a construction block is suitable for eliminating unproductive time-delays under the constrained resources (e.g., laborer, equipment). A case study presents a network model representing a three segmented RC frame work, and result obtained from the simulation experiment.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.256-261
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• 2008

The curtain-wall work has been more frequently applied in the construction industry since demand of high-rise buildings has been increased. The curtain-wall work is usually performed with the frame work simultaneously for reducing construction period, but it might be delayed because of several problems caused by interference of process. However, there is not an appropriate tool which can be used by a work manager for adjusting quantity of the construction equipments or the workers when the curtain-wall work was delayed. To resolve this problem a construction simulation anticipating and analyzing potential problems before starting the work can be applied in the curtain wall work. This research suggests a general model for the curtain-wall work by using construction simulation and produces a combination of construction equipments and workers which can estimate optimum work productivity.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.179-179
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• 2012

국내에는 나노 분말 제조를 위한 RF 열플라즈마 시스템 제조 기술이 확보되어 있지 않고, 또한 나노 파우더 제조를 위한 공정 기술 역시 외국 업체에 전적으로 의존하고 있다. 본 연구에서는 나노 분말 제조를 위한 RF 열 플라즈마 토치 시스템 개발과 고품질의 나노 파우더 합성 공정 기술을 확립하여 필요 기관에 제공하는데 있다. 80 kW RF Plasma torch system의 설계 및 제작을 위해 플라즈마 Simulator인 CFD-ACE+를 이용하여 플라즈마 토치 및 반응로 내의 온도 분포, 유체 유동, 열전달 등의 해석을 통해 플라즈마 토치 및 반응로의 반경 및 길이, 구조의 설계 값을 도출하여 반응로를 설계하여 RF 파워, RF 플라즈마 토치(Torch), 반응기(Reactor), 사이클론(Cyclone), 포집부(Collector), 열교환기 및 진공배기 시스템으로 구성하였다. Si 나노 소재의 경우, 이차전지 음극재에 적용이 가능한 대표적인 소재로서 높음 비용량과 충/방전시 부피팽창을 감소시킬 수 있어 이차전지의 고용량 구현을 위해서는 가장 중요한 소재중 하나로 많은 관심 재료로 평가 받고 있다. 따라서 본 연구에서는 상용화된 Si 원료 powder를 사용하여 고상 분체 공급 장치를 통하여 고온의 플라즈마를 통과시켜 기상화 및 결정화과정을 통해 Si 나노분말을 제조하였다. 공정 변수로서 공정압력 및 플라즈마 power, Gas의 변화량에 따른 나노 분말의 제조 특성에 대한 실험을 진행한 후 제조된 나노 분말을 비표면적측정(BET) 및 SEM 측정 결과 분석을 통하여 시스템 특성을 파악하였으며 제조된 Si 나노 파우더는 이차전지 음극재로서 770 mAh/g의 용량과 93%@50 cycle 수준의 유지율을 나타내었다.

• Korean Chemical Engineering Research
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• v.58 no.4
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• pp.642-650
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• 2020

In general, the circulation path of the fluidized particles in a CFB (Circulating Fluidized Bed) boiler is such that the particles entrained from a combustor are collected by a cyclone and recirculated to the combustor via a sealpot which is one of non-mechanical valves. However, when a fluidized bed heat exchanger (FBHE) is installed to additionally absorb heat from the fluidized particles, some particles in the sealpot pass through the FBHE and then flow into the combustor. At this time, in the FBHE operated in the bubbling fluidization regime, if the heat flow is not evenly distributed by poor mixing of the hot particles (800~950 ℃) flowing in from the sealpot, the heat exchanger tubes would be locally heated and then damaged, and the agglomeration of particles could also occur by formation of hot spot. This may affect the stable operation of the circulating fluidized bed. In this study, the unevenness of heat flow arising from structural problems of the FBHE of the domestic D-CFB boiler was found through the operating data analysis and the CPFD (Computational Particle Fluid Dynamics) simulation using Barracuda VR. Actually, the temperature of the heat exchanger tubes in the FBHE showed the closest correlation with the change in particle temperature of the sealpot. It was also found that the non-uniformity of the heat flow was caused by channeling of hot particles flowing in from the sealpot. However, it was difficult to eliminate the non-uniformity even though the fluidizing velocity of the FBHE was increased enough to fluidize hot particles vigorously. When the premixing zone for hot particles flowing in from the sealpot is installed and when the structure is changed through the symmetrization of the FBHE discharge line for particles reflowing into the combustor, the particle mixing and the uniformity of heat flow were found to be increased considerably. Therefore, it could be suggested that the structural modification of the FBHE, related to premixing and symmetric flow of hot particles, is an alternative to reduce the non-uniformity of the heat flow and to minimize the poor particle mixing.