• Title/Summary/Keyword: Emergency mode

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Design of Anti-Surge Valve for FPSO Fuel Gas Compressor System (FPSO용 연료가스압축 시스템을 위한 서지방지 밸브 설계)

  • Park, Hyung-Wook;Cho, Jong-Rae;Lee, Seung-Min;Park, Jong-Jin
    • Journal of Advanced Marine Engineering and Technology
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    • v.35 no.4
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    • pp.443-450
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    • 2011
  • Fuel gas compressor system is applied to medium FPSO. In order to avoid surge, this system used the anti-surge valves. When surge occurs it may lead to system's fracture. So anti-surge valves are evaluated structural strength and structural safety. Especially, in emergency mode, valves are must be guaranteed structural safety. In this study, structural strength and structural safety of anti-surge valve was evaluated using the numerical simulation. Unigraphics NX 4.0 was used as Geometrical models, structural strength and structural safety calculation were carried out by ANSYS Workbench 12.1. The ASME Boiler & Pressure Vessel Code is refer to allowable strength and safety factor of the valves.

Integrity Assessment of Spread Footing Pier for Scour Using Natural Frequency (고유진동수를 이용한 확대기초 교각의 세굴 건전성 평가)

  • Park, Byung-Cheol;Oh, Keum-Ho;Park, Seung-Bum
    • Journal of the Korean Society of Hazard Mitigation
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    • v.5 no.2 s.17
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    • pp.29-35
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    • 2005
  • In Korea more than ninety bridges are collapsed every year by flood, which causes the scour of pier foundation. Researches on the quantitative assessment method to assess the integrity of bridge against scour have not been organized systematically in the bridge design practice and maintenance area. In this study, dynamic characteristics assessment experiments are carried out as an emergency inspection method to assess the integrity of the pier foundation for scour after a flood. According to the dynamic characteristics assessment experiment, which simulates foundation scour of the spread footing pier, foundation scour can be evaluated by the first mode natural frequency of the pier.

Design of LED Driving Circuit using Voltage Controlled Ring Oscillator and Lighting Controller (전압제어 링 발진기를 이용한 LED구동회로 및 조명제어기설계)

  • Kwon, Ki-Soo;Suh, Young-Suk
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.4
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    • pp.1-9
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    • 2010
  • An LED driving and control circuit has been developed. The LED driver has a new PWM circuit for current control of LED columns with dimming, current and thermal control, and communication functions. The PWM circuit is composed of two ring oscillator and one counter which can be constructed using basic digital logic components. In addition, it has the functions of remote control mode such as ON, OFF, emergency and power saving modes by the serial communication. The PWM generator and control circuit have been designed and fabricated 0.35[${\mu}m$] Magnachip/Hynix digital IC fabrication process. The LED driving and control board using the developed chip is fabricated and tested successfully.

Waterhammer for the Intake Pumping Station with the Pump Control Valve (펌프제어밸브를 사용한 취수펌프장에서의 수격현상)

  • Kim, Kyung-Yup;Oh, Sang-Hyun
    • The KSFM Journal of Fluid Machinery
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    • v.4 no.4 s.13
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    • pp.16-21
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    • 2001
  • The field tests on the waterhammer were carried out for PalDang intake pumping station of the metropolitan water supply 5th stage project. The pumping station was equipped with the pump control valve as the main surge suppression device and the surge relief valve as auxiliary. However, the pump control valve had not been early controlled in the planned closing mode, and the slamming occurred to the valve which abruptly closed during the large reverse flow. Because the pressure wave caused by the pump failure was superposed on the slam surge, the upsurge increased so extremely that the shaft of the valve was damaged. It was desirable that the surge relief valve was installed in the pumping station or near the pump exit for the delay of response. After reforming the oil dashpot of the pump control valve, the sliming disappeared and the measured pressure was in fairly good agreement with the results of simulation. In case of three pumps for ${\phi}2,600$ pipeline being simultaneously tripped, the pressure head in the pumping station increased to 95.6 m, and the upsurge caused by the emergency stop of four pumps for ${\phi}2,800$ pipeline was 89.6m. We concluded that the pumping station acquired the safety and reliability for the pressure surge.

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Vehicle Communication System Implementation for u-TSN and Its Performance Evaluations (u-TSN에서 차량 통신시스템 구성 및 성능평가)

  • Jeon, Sung-Hee
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.48 no.7
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    • pp.35-40
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    • 2011
  • In u-TSN environment, the communication between vehicle terminal and roadside equipment is very important to support prompt service and to secure road traffic information in real-time upon organizing traffic system. This study suggested V2I or I2V communication service scenario for performance test on vehicle communication system as well as V2V inter-vehicle communication service scenario for emergency information transmission which requires rapidity and accuracy. After implementing real inter-vehicle communication system, we performed vehicle communication experiment following suggested communication service scenario to test the performance. Consequently, we could draw out the optimal transmission mode setup condition, and the result can be applied to the development of stable and efficient u-TSN vehicle communication system.

Analysis of Timing Constraints for Timely Collaboration among Web-Based Distributed Business Systems (웹기반 분산 기업시스템의 적기협력을 위한 시간 제약 조건의 분석)

  • Suh, Tae-Jung;Lee, Dong-Woo
    • 대한공업교육학회지
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    • v.33 no.2
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    • pp.232-247
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    • 2008
  • Timely collaboration among businesses is required these days such as in B2B E-Commerce. That is, emergency requests or urgent information among businesses should be processed in an immediate mode. In this paper we investigate the semantics on timing constraints of timely collaboration among businesses in terms of event, data, and action and present ECA rule construction related to the timing constraints and its violation. The prototype is implemented using web-based active functionality component.

Fast Recovery Routing Algorithm for Software Defined Network based Operationally Responsive Space Satellite Networks

  • Jiang, Lei;Feng, Jing;Shen, Ye;Xiong, Xinli
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.7
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    • pp.2936-2951
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    • 2016
  • An emerging satellite technology, Operationally Responsive Space (ORS) is expected to provide a fast and flexible solution for emergency response, such as target tracking, dense earth observation, communicate relaying and so on. To realize large distance transmission, we propose the use of available relay satellites as relay nodes. Accordingly, we apply software defined network (SDN) technology to ORS networks. We additionally propose a satellite network architecture refered to as the SDN-based ORS-Satellite (Sat) networking scheme (SDOS). To overcome the issures of node failures and dynamic topology changes of satellite networks, we combine centralized and distributed routing mechanisms and propose a fast recovery routing algorithm (FRA) for SDOS. In this routing method, we use centralized routing as the base mode.The distributed opportunistic routing starts when node failures or congestion occur. The performance of the proposed routing method was validated through extensive computer simulations.The results demonstrate that the method is effective in terms of resoving low end-to-end delay, jitter and packet drops.

A Study of Smoke Exhaust Facility Operation of Subway Platform with Installation of Platform Screen Door (승강장 스크린도어 설치에 따른 배연설비운영에 대한 연구)

  • Rie, Dong-Ho;Ko, Jae-Woong;Kim, Ha-Young
    • Journal of the Korean Society of Safety
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    • v.21 no.1 s.73
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    • pp.35-40
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    • 2006
  • A study on fire phenomena in a subway transit mass station has been carried out as a part of disaster prevention plan at the subway station. The ventilation facilities installed in both the platform and the trackway are designed to convert into a smoke exhaust system in emergency situation, creating such an environment as necessary for evacuation. 3 dimensional Numerical Simulations based on the CFD are carried out using a simulation tool, Fire Dynamic Simulator. Additionally, four different vent modes are made and performances are compared with the original design mode and each other to find better operation of vents at both the platform and the trackway in case of fire. From the result, an vent operational characteristics under the condition of installed PSD is clarified for the effective smoke and heat removal from the platform area compared with non installed PSD.

The 1D-3D Simulation for Smoke Ventilation in a Rescue Station of a Railroad Tunnel under the Fire (장대 터널 내 구난역의 열차 화재 시 제연을 위한 1D-3D 연계 해석)

  • Jung, Jae-Hyuk;Hur, Nahm-Keon;Lee, Jung-Pyo;Kim, Jin-Kon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.22 no.10
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    • pp.665-671
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    • 2010
  • In the present study a 1D-3D numerical simulation was performed to analyze the fire safety in a rescue station of a long railroad tunnel equipped with a mechanical ventilation. The behavior of hot air was studied for the emergency operation mode of ventilation system in case of fire in the rescue station. The 1D simulation was carried out for entire tunnel region. Detailed 3D CFD simulation was performed for the rescue station area in the central region of the tunnel by using the result of the 1D simulation as the boundary condition of the 3D simulation. Various type of cross passage installation were evaluated for the prevention of smoke diffusion to suggest the optimized interval of the cross passages in the rescue tunnel.

Effects of local structural damage in a steel truss bridge on internal dynamic coupling and modal damping

  • Yamaguchi, Hiroki;Matsumoto, Yasunao;Yoshioka, Tsutomu
    • Smart Structures and Systems
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    • v.15 no.3
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    • pp.523-541
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    • 2015
  • Structural health monitoring of steel truss bridge based on changes in modal properties was investigated in this study. Vibration measurements with five sensors were conducted at an existing Warren truss bridge with partial fractures in diagonal members before and after an emergency repair work. Modal properties identified by the Eigensystem Realization Algorithm showed evidences of increases in modal damping due to the damage in diagonal member. In order to understand the dynamic behavior of the bridge and possible mechanism of those increases in modal damping, theoretical modal analysis was conducted with three dimensional frame models. It was found that vibrations of the main truss could be coupled internally with local vibrations of diagonal members and the degree of coupling could change with structural changes in diagonal members. Additional vibration measurements with fifteen sensors were then conducted so as to understand the consistency of those theoretical findings with the actual dynamic behavior. Modal properties experimentally identified showed that the damping change caused by the damage in diagonal member described above could have occurred in a diagonal-coupled mode. The results in this study imply that damages in diagonal members could be detected from changes in modal damping of diagonal-coupled modes.