• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.22 no.3
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• pp.23-28
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• 1986

This paper describes on the measurement of the deck vibration produced by the main engine vibration of stern trawler MjS SAE-BA-DA (2,275GT, 3,600PS) while the ship is cruising and drifting. The obtained results are as follows; 1. The deck vibration level was the highest point at vertical line which pass main engine and the lowest point at vertical line which pass top bridge while the crusing. 2. The vibration source level of the main engine, screw shaft and screw propeller were respectively 110, 90 and 80% while the crusing. 3. The main deck vibration pressure level at the check points 2, 20, 30, 40, 60, 70, 80, 86m from the bow to stern was respectively 9, 8, 7, 10, 22, 45, 18, 23%. 4. The frequency distributions of the rr.ain engine, screw shaft, screw propeller vibration were from 3 Hz to 10 KHz, predominant frequency was 1 KHz, each vibration accelration the highest level were respectively 1. 3, 0.8, 0.5 $mm/s^2.$ 5. The predominant frequency distributions of the main deck, second deck, bridge deck and top bridge deck-s vibration were from 10 to 30 Hz, and each vibration accelration level were respectively 0.7, 0.05, 0.07, 0.04 $mm/s^2.$

• Journal of Korea Fishing Vessel Association
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• v.29
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• pp.15-20
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• 1986

This paper describes on the measurement of the deck vibration produced by the main engine vibration of stern trawler MIS SAE-BA-DA (2,275GT, 3,600PS) while the ship is cruising and drifting. The obtained results are as follows; 1. The deck vibration level was the highest point at vertical line which pass main engine and the lowest point at vertical line which pass top bridge while the crusing. 2. The vibration source level of the main engine, screw shaft and screw propeller were respectively 110, 90 and 80% while the crusing. 3. The main deck vibration pressure level at the check points 2, 20, 30, 40, 60, 70, 80, 86m from the bow to stern was respectively 9, 8, 7, 10, 22, 45, 18, 23%. 4. The frequency distributions of the main engine, screw shaft, screw propeller vibration were from 3Hz to 10KHz, predominant frequency was 1KHz, each vibration accelration the highest level were respectively 1.3, 0.8, 0.5mm/$S^2$. 5. The predominant frequency distributions of the main deck, second deck, bridge deck and top bridge deck's vibration were from 10 to 30Hz, and each vibration accelration level were respe¬ctively 0.7, 0.05, 0.07, 0.04mm/$S^2$.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.771-776
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• 2010

Since the importance of seismic design is greater, dynamic analysis is more widely using than past. The input motion is one of the most important factors of dynamic analysis. However, in Korea input motions are selected from U.S. and Japan those are captured from large magnitude earthquakes without considering seismic environment or generated in frequency domain. In this research, the methodology for generating input motions those are considered seismic environment and design code is proposed. The seismic environment compatibility is considered by performing deaggregation and the design code compatibility is considered by time-domain artificial time history accelration generation method. The results shows that seismic environment and design code compatible input motions are successfully generated.

• Nuclear Engineering and Technology
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• v.38 no.2
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• pp.195-200
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• 2006

In order to confirm the integrity of IRWST following a severe accident, the hydrogen behavior inside and around the IRWST has been investigated for an SBO accident. A detailed containment model, including 18 control volumes for IRWST, has been developed. Analysis results show that the peak hydrogen concentration is about 57% during the core melting period. The combustion regime shows that flame acceleration and DDT are possible in the IRWST. The flame acceleration criterion is met when the peak hydrogen concentration occurs; the 7 -DDT criterion is also met during some periods. These results show certain measures may be required to assure IRWST integrity against an SBO accident.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.04a
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• pp.52-57
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• 1998

Becaruse of the continual occurrence of minor and moderate earthquake in Korean peninsula, it is generally considered that Korean is nor located in safe region against probable earthquake and more, even though being recognized as a safe contry in earthquake. It is in particular noted that nowadays there has been much concern about undesirable disaster due to unexpected earthquake since the disaster of 1995 Kobe earthquake. Thus, the objective of this research is to develop appropriate design spectrum which could be practicably used in seismic design of important structures taking into consideration of local physical characteristics. Particularly, we have to keep in mind the lessons from 1985 Mexico earthquake which had disregarded deep research on local ground conditions, being a possible magnification phenomena of ground motions in weak soil layer. Various spectra has been described based on the analysis of historical earthquakes, and appropriate design spectrum has been proposed herein.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.5
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• pp.43-52
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• 2019

Cryogenic propellant rockets utilize a natural circulation loop of cryogenic fluid to cool the engine inlet temperature before launch. The geometric information about the circulation system, such as length and diameter of the pipes and the heat input to the system, defines the mass flow rate of the natural circulation loop. We performed experiments to verify the natural circulation mass flow rate and compared the results with the analytical results. The comparison of the mass flow rate between experiments and numerical simulations showed a 12% offset. We also included a prediction of the natural circulation flow rate in the low-gravity section and in the acceleration section in the upper stage of the launch vehicle. The oxygen tank should have 100 kPa(a) of pressure in the acceleration section to maintain a high flow rate for the natural circulation loop. In the low-gravity section, there should be an optimal tank pressure that leads to the maximum natural circulation flow rate.