• Title/Summary/Keyword: characteristic energy

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Theoretical Characteristics of the Probe with Respect to the Engine Oil States (엔진오일 상태에 대한 프로브의 이론 특성)

  • Kim, Young-Ju
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.15 no.1
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    • pp.22-24
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    • 2012
  • Depending on the status of the engine oil, the dielectric constant is changed. Dielectric constant of oil is related to the characteristic impedance of the probe and the characteristic impedance of the probe determines the reflected signal. In this paper, we derive an equivalent circuit of the probe and using the dielectric constant obtained by measuring the capacitance, the theoretical reflection coefficient of the probe was calculated. In the results, if the engine oil is deteriorated, we can see that the reflection coefficient is increased.

An Analysis of Ice Impact Force Characteristics for the Arctic Structure Shape (극지 구조물 형상에 대한 빙충격 하중 특성 분석)

  • Jeong, Seong-Yeob;Cho, Seong-Rak
    • Journal of the Society of Naval Architects of Korea
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    • v.49 no.6
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    • pp.469-477
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    • 2012
  • This paper describes the characteristic analysis of ice impact force for the Arctic structure shape. In the present study an energy method has been used to predict the impact force during the ice-structure collision. This study also employs two concepts for reference contact area and normalized stress in analysis procedure. The influences of factors, such as impact velocity, full penetration depth, structure shape and ice floe size, are investigated. Full penetration occurs, particularly at lower impact velocity when ice thickness increase. But "typical size" ice floe does not expected ever to achieve full penetration during the impact procedure. The structure shape is the dominant factor in ice impact force characteristic. The results for various ice-structure collision scenarios are analyzed.

Optimal Design of Battery of Fuel Cell Electric Vehicle Based on Fuel Cell Dynamic Characteristic Model (연료전지 과도 특성 모델링 기반 FCEV용 배터리 용량 최적 설계)

  • Ko, Jeong-Min;Kim, Jong-Soo;Lee, Young-Kuk;Lee, Byung-Kuk
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.9
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    • pp.1714-1719
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    • 2009
  • In this paper, methodology of battery optimal designing is proposed. Fuel cell model including dynamic characteristic is developed and load model is produced by considering driving schedule. Using these models, required energy of load and supplying energy from fuel cell are analyzed by comparing simulation results. Also parameter of fuel cell model is changed variously and battery capacity is calculated in each cases. And methode of battery optimal designing is presented by regarding dynamic characteristic of fuel cell.

Performance evaluation of MPCM to apply for radiant floor heating system (바닥난방시스템 적용을 위한 MPCM 성능평가)

  • Jeong, Su-Gwang;Jeon, Ji-Soo;Kim, Su-Min
    • 한국태양에너지학회:학술대회논문집
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    • 2012.03a
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    • pp.475-479
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    • 2012
  • Thermal energy storage (TES) systems using Microencapsulated phase change material (MPCM) have been recognized as one of the most advanced energy technologies in enhancing the energy efficiency and sustainability of buildings. We examined a way to incorporate MPCMs with building materials through application for wood-based flooring. Wood-based flooring is commonly used for floor finish materials of residential buildings in Korea. However, wood-based flooring has not performed the characteristic of heat storage. This study is aimed at manufacturing high thermal efficiency wood flooring by increasing its heat storage using MPCM. As a result, this study confirmed that MPCM is dispersed well in adhesive through the scanning electron microscopy analysis. From the differential scanning calorimetry analysis, it can be confirmed that this composite has the characteristic of a thermal energy storage material. Also, we analyzed how this composition was formed by physical combination through the Fourier transform infrared analysis. Also, we confirmed the bonding strength of the material by using the universal testing machine.

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A Study on the Effect of Wind Turbulence Intensity on the Power Performance of Wind Turbine System (풍력발전시스템 출력에 대한 난류강도의 영향 연구)

  • Hyun, Seung-Gun;Ju, Young-Chu;Kim, Keon-Hoon
    • Journal of the Korean Solar Energy Society
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    • v.32 no.4
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    • pp.17-23
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    • 2012
  • The installed capacity of wind turbines in Korea are growing and enlarging by the central government's supporting program. But the majority area having the abundant wind energy resources is composed of mountainous and complex district, thus the turbulence intensity of there is so high and belongs to the turbulence characteristic A category of IEC design requirement. This paper presents the effect of the turbulence intensity on the power performance of a wind turbine system. Particularly, the effect of the power curve of the wind turbine system due to the turbulence intensity has analyzed. As a result, the power curve has a high turbulence characteristic shows the lower value than normal one in high wind speed regime and the AEP will be reduced at the relatively high turbulence area.

Development of Analysis Program of Dynamic Characteristic for the Propulsion Shafting System (선박추진축계 동특성 분석 프로그램 개발)

  • Ha, Jeong-Min;Lee, Jeong-Myeong;Lee, Jeong-Hoon;Kim, Yong-Whi;Ahn, Byeong-Hyun;Choi, Byeong-Keun;Kim, Won-Chul
    • Journal of Power System Engineering
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    • v.18 no.2
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    • pp.57-61
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    • 2014
  • Due to the changes of marine transportation industry, it requires ship in larger scale and high speed. In order to operate efficiently, the engine should be work in high power and high horse power. The increase of the number of the propeller blades and the pitch of the screw and the weight, vibration of shafting problems occurs. To evaluate the safety of the system through analyzing the dynamic characteristics propulsion shafting system, was used to prove or to verify the Lalanne & Ferraris model validation.. It indicates that the Program through Campbell diagram and Critical speed map, Root rocus map, to ensure the reliability of the experimental model.