• Journal of the Society of Naval Architects of Korea
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• v.57 no.6
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• pp.373-380
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• 2020

We have developed the hybrid prototype load cell structures. These developed load cell structures may increase the reliability of the load sensing by deriving the load values through the double sensing method through the vertical maximum deflection and bending stress of the simple beams. For this purpose, the structure design was performed so that the load value, the deflection and stress value could be output to the same value through the optimal structure design. The structurally designed dimensions reaffirmed the accuracy of the design through the structural analysis program and the matching of the load value and the deflection value. Based on the designed structural dimension, the prototype form was constructed through laser cutting and production using hot rolled steel materials. The developed prototype load cell structure can be used as good educational material in various subjects such as material mechanics, steel structure design, measurement engineering, and mechatronics engineering. It is also believed that the measurement system ideas can inform the occurrence of errors in the event of a problem, and if a major accident caused by a sensing error is predicted, it will show good utilization to prevent accidents.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.4
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• pp.407-418
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• 2017

Battery heat management is essential for high power and high energy battery system because it affects its performance, longevity, and safety. In this paper, we investigated the temperature of the 18650 Lithium Ion Battery Module used in a Energy Storage System (ESS) and the cooling method to minimize cell-to-cell temperature variation of battery module. For uniform temperature distribution within a battery module, the flow direction of the coolant in a battery module has been changed according to the time interval, and studied the effect of the cooling method on the temperature uniformity in a battery module which includes a number of battery cells. The experimental results show that bi-directional battery cooling method can effectively reduce the cell-to-cell temperature variation compared with the one-directional battery cooling. Furthermore, it is also found that bi-directional battery cooling can reduce the maximum temperature in a battery module.

• Korean Institute of Interior Design Journal
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• v.20 no.5
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• pp.23-33
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• 2011

Starting with 21st Century, the role of the design has been widened and designers began to regard the psychological and behavioral factors as main design considerations. These factors are the core elements especially in designing interactive space. This research proposed the user-centered design methodology for interactive space. It developed Programming Process for Supporting Interactive Behaviors. To compose the process, this research analyzed the influential factors on the interactivity and the results were applied on the process. This newly proposed Programming Process contains four basic stages which are 'Opportunity Identification Cell', 'Intersubject Cell', 'Interaction & Interface Cell', and 'Programming Solution Cell'. More detailed tasks are also specified for each stage. This research asserts that the design process for Interactive space should differ from the past design processes in the fact that it puts much more attention on systemizing the psychological and behavioral elements than before. Therefore the design process for Interactive space should be reinforced with the data related to these psychological and behavioral understandings. The Programming Process of this paper is an attempt to enlarge the roles of these data in designing interactive space, and thus it is an attempt to accommodate the contemporary user-centered design paradigm.

• KSBB Journal
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• v.27 no.3
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• pp.186-194
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• 2012

Various human host cell lines, which are more effective than the other original human cell lines, have been developed and used. Highly efficient human cell line can be obtained from the fusion between human embryonic kidney 293 (HEK293) and human Burkitt's lymphoma cells (Namalwa). Fused cell line has the advantages of both cell lines such as the high transfection efficacy of HEK293 cells and the constitutive expression of Epstein-Barr virus (EBV) genome which is related with high expression of target protein and anti-apoptotic growth of Namalwa cells. In this study, characterization of two original cell lines was performed by using design of experiment (DOE) considering cell maintenance, media development, optimization of culture condition, and scale-up. The formation of aggregates was apparent with high glutamine concentration at more than 6 mM. Supplementation of hydrolysates showed positive effects on the growth performances of HEK293 cells. On the contrary, Namalwa cells showed negative results. It was confirmed that Namalwa cells were more sensitive to lower temperature at $35^{\circ}C$ and hyperosmotic condition over 260 mOsm/kg. In addition, both cell lines showed limited growth in 3-L bioreactor due to shear stress.

• The KSFM Journal of Fluid Machinery
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• v.15 no.5
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• pp.11-19
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• 2012

The main function of fuel cell manifold is to render reactants distribution as uniform as possible into a fuel cell stack. The purpose of this study is to numerically investigate the effects of stack manifold design on reactants distribution within a fuel cell stack. Four manifold designs with different manifold entrance shapes (expansion or diffuser) and different values of the extra width between the cell outer channel and manifold side wall are considered and applied to the fuel cell stack consisting of 50 cells. Since the fuel cell stack geometry involves several millions of grid points for numerical calculations, a parallel computing methodology is employed to substantially reduce the computational time and overcome the memory requirement. The numerical simulations are carried out and calculated results clearly demonstrate that both the manifold entrance shape and extra width have a substantial influence on manifold performance, controlling the degree of flow separation and entrance length for fully developed flow in the manifold channel. Finally, we suggest the optimum design of fuel cell manifold based on the simulation results.

• Journal of the Korean Society of Visualization
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• v.19 no.2
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• pp.56-62
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• 2021

Solid oxide fuel cells (SOFCs) is the high efficiency fuel cell operating at high temperatures ranging from 700-1000℃. Design of the flow paths of the fuel and air in SOFCs is important to improve cell performance and prevent cell degradation. However, the uneven distribution of current density in the traditional type having one inlet and outlet causes cell degradation. In this regard, the parallel flow path with two inlet and outlets was designed and compared to the traditional type based on computational fluid dynamics (CFD) simulation. To check the cell performance, hydrogen distribution, velocity distribution and current density distribution were monitored. The results validated that the parallel designs with two inlets and outlets have a higher cell performance compared to the traditional design with one inlet and outlet due to a larger reaction area. In case of uniform-type paths, more uniform current density distribution was observed with less cross-sectional variation in flow paths. In case of contracted and expanded inflow paths, significant improvement of performance and uniform current density was not observed compared to uniform parallel path. Considering SOFC cell with uniform current density can prevent cell degradation, more suitable design of SOFC cell with less cross-sectional variation in the flow path should be developed. This work can be helpful to understand the role of flow distribution in the SOFC performance.

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.3
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• pp.279-285
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• 2006

Recirculation for the unreacted fuel is necessary to improve the overall efficiency of the fuel cell system and to prevent fuel starvation since the fuel cell for a vehicle application is a closed system. In case of the automotive fuel cell, the ejector which does not require any parasitic power is good for the performance improvement and easy operation. It is essential to design the customized ejector due to the lack of the commercial ejector corresponding to the operating conditions of the fuel cell systems. In this study, the design methodology for the ejector customized to an automotive fuel cell is proposed. The model based sensitivity analysis prevents the time-consuming redesign and reduces the cost of developing ejector. As a result, the customized ejector to meet the desired performance within overall operating range has developed for the PEMFC automotive system.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.1
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• pp.26-34
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• 2008

This study presents an aerodynamic design and an experimental performance test of a turbo air compressor consisted of mixed-flow impeller and curved diffuser for the PEM fuel cell vehicle application. Many studies compare the efficiency, cost or noise level of high-pressure and low-pressure operation of PEM fuel cell systems. Pressure ratio 2.2:1 is considered as design target The goal of compressor design is to enlarge the flow margin of compressor from surge to choke mass flow rate to cover the operational envelope of FCV. Large-scale rig test is performed to evaluate the compressor performance and to compare the effects of compressor exit pipe volume to stall or surge characteristics. The results show that the mixed-flow compressor designed has large flow margin, and the flow margin of compressor configuration with small exit volume is larger than that with large exit volume.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.280-283
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• 2008

This study is concerned with development of air supply system in 250kW MCFC fuel cell system. The turbo blower is decided as an air supply system to increase the efficiency of fuel cell system. The turbo blower consists of an impeller, two vaneless diffuser, a vaned diffuser and a volute. The cascade diffuser is used to raise the efficiency of turbo blower. An aerodynamic design was done by applying the repeating design procedure including a meanline design, a 3D geometry generation and fluid dynamic calculation. It is confirmed from meanline and 3D flow analysis results that the operating range is enough and design requirements are successfully achieved. The performance test results were also included in this paper.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.178-183
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• 2004

The main objective of the present study is to analyze the feasibility of fuel cell powered vehicle, which leads to carry out system design and performance analysis. The major design concepts which include battery, driving motor, and fuel cell module are analyzed and discussed for the future development. The traction power of fuel cell vehicle is calculated according to the driving courses specified. Further, the fuel cell stack is analyzed to determine the capacity of stack as a function of velocity for the appropriate power required.