• Journal of the Society of Naval Architects of Korea
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• v.61 no.2
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• pp.125-134
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• 2024

The Safe Operating Envelope (SOE) combined with Short-Take-Off and Vertical Landing (STOVL) performance is an essential consideration of a light aircraft carrier for design of hull shape with excellent seakeeping performance in terms of naval air operations as well as traditional naval ship missions such as Transit and Patrol (TAP), and Replenishment at Sea (RAS) and so on. A variety of procedures are systematically combined to determine SOE considering rather complicated missions associated with operation of aircraft onboard. The evaluation of take-off and landing safety missions onboard should consider wind effect on deck and severer seakeeping indices and standards compared with conventional naval ships. In order to support take-off and landing missions, various support activities of the crews are required. So, additional evaluation is needed for indicators such as MSI(Motion sickness Index) and MII(Motion Induced Interruptions), which are quantitative indicators of work ability that appear as a result of motion response. In this study, a standard procedure is developed including the seaworthiness performance indicators, standards, and evaluation procedures that should be considered during design of STOVL aircraft carrier. Analysis results are discussed in terns of air-wake on deck as well as seakeeping indices associated with design parameter changes in view of conceptual design of a light aircraft carrier.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.4
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• pp.445-453
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• 2016

Objectives: The objective of this study is to assess relative safety level of the decompression tables in Ministry of Employment and Labor Public Notice No. 2014-28 in comparison with overseas decompression tables. Methods: Decompression tables in the Public Notice No. 2014-28 were compared with examples from Japan, the USA, Canada, and France in terms of ascent rate, surface intervals after exceptional exposures, oxygen decompression and allowable partial pressure, depth limits in air diving, no-decompression limits, and decompression time and methods. Results: Public Notice No. 2014-28 does not include air diving depth limits, exceptional exposure limits, mandatory surface intervals after exceptional exposures, oxygen decompression, and surface decompression schedules. Its decompression time was found to be the shortest among the five decompression tables. Conclusions: Public Notice No. 2014-28 has the lowest safety level in comparison with overseas decompression tables. Deck decompression chambers are not applicable due to no regulations on surface interval and oxygen use in the chamber for decompression.

• The Journal of the Acoustical Society of Korea
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• v.43 no.1
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• pp.60-71
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• 2024

The present study aims to investigate the level difference of floor impact noises of composite floor structure using EVA resilient materials. In order to this, four different types of resilient materials were designed combining PET, PP sheet and EVA mount including Flat type, Deck type, Cavity type and Mount type. Totally 9 different samples were made for acoustic measurements which were carried out twice with bang-machine and impact ball as the heavy-weight floor impact noise sources. All the floor impact noise measurements were undertaken at the authentication institution. As a result, concerning Flat and Cavity types, it was found that 2 dB ~ 5 dB of heavy-weight floor impact noise was reduced supplementally when PET was added, while floor impact noise larger than 50 dB was acquired when single resilient material was used. Especially, most high performance was obtained for Mount type with 1st grade of light-weight floor impact noise and 2nd grade of heavy-weight floor impact noise. This is because of material property with low dense PET sound absorption materials which fill all around EVA mounts. Also, it was considered that this results are due to the sound impact absorption by the both EVA mounts and the air cavity between EVA mount and PP sheet. Also, it was found that at least 36 EVA mounts per 1m2 area of resilient panel make more noise reduction of heavy-weight floor impact noises.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.1
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• pp.8-18
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• 2015

Reduction of the fuel oil consumption and corresponding greenhouse gas exhausted from ships is an important issue for today's ship design and shipping. Several concepts and devices on the superstructure of a container ship were suggested and tested in the wind tunnel to estimate the air drag reduction. As a preliminary performance evaluation, air drag contributions of each part of the superstructure and containers were estimated based on RANS simulation respectively. Air drag reduction efficiency of shape modification and add-on devices on the superstructure and containers was also estimated. Gap-protectors between containers and a visor in front of upper deck were found to be most effective for drag reduction. Wind tunnel tests had been carried out to confirm the drag reduction performance between the baseline(without any modification) configuration and two modified superstructure configurations which were designed and chosen based on the computation results. The test results with the modified configurations show considerable aerodynamic drag reduction, especially the gap-protectors between containers show the largest reduction for the wide range of heading angles. RANS computations for three configurations were performed and compared with the wind tunnel tests. Computation result shows the similar drag reduction trend with experiment for small heading angles. However, the computation result becomes less accurate as heading angle is increasing where the massively separated flow is spread over the leeward side.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.6
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• pp.289-296
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• 2017

This study aimed to analyze the deck floor heating system of an outdoor swimming pool in terms of the thermal capacity/output and the surface temperature distribution based on the outdoor temperature, to design for anti-freezing during winter. Through the transient heat transfer simulation with PHYSIBEL and theoretical equations, the surface temperature distribution of the floor heating system at two outdoor conditions in Jeju, were calculated and evaluated. The results indicate that the specific thermal output required for maintaining $4^{\circ}C$ surface temperature at the design outdoor temperature of $0.1^{\circ}C$, was about $90W/m^2$. This performance analysis can be applied for future design criteria, including optimizations of system capacity and size.

• Special Issue of the Society of Naval Architects of Korea
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• 2011.09a
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• pp.43-46
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• 2011

The noise characteristics of multi-purpose dive support vessel show the different patterns such as types of noise sources, accommodation arrangement and etc due to its operation. Especially, the tunnel and retractable thruster for the dynamic positioning should be considered at the noise analysis. The floating floor is selected as the main measure of noise reduction and is constructed at the deck near the noise sources. In this paper, the noise analysis of dive support vessel is based on the estimation of noise sources and floating floor and SEA (Statistical Energy Analysis) is used for analysis of the air-born noise and structure-borne noise. The noise analysis of air conditioning system is also carried out and the noise results of cabin room are reviewed.

• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2504-2515
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• 2023

In past years the Paul Scherrer Institute (PSI, Switzerland) and the Karlsruhe Institue of Technology (KIT, Germany)) collaborated to develop a model to account for the active role of nitrogen in the air oxidation of a Zircalloy cladding. The "PSI-KIT Nitriding Model for Zirconium based Fuel Cladding" model was implemented at PSI into PSI-MELCOR 1.8.6. In order to make a preliminary evaluation of the effect of the new model on the evolution of full-scale spent fuel pool accidents, one spent fuel pool event was analyzed using the PSI research version of PSI-MELCOR 1.8.6, which includes the nitriding model. To adapt an existing input deck for the calculations, a sensitivity study was conducted to find an optimal nodalization for the analyses. The nitriding model results were compared to those calculated with the MELCOR 1.8.6-PSI without the new nitriding model. The results demonstrate the effect of the nitriding reactions in spent fuel pool accident progression. Moreover, they confirm the impact of ZrN formation during cladding oxidation in air when the oxidation reactions lead to oxygen starvation inside the fuel assemblies. The nitriding reaction led to higher chemical heat generation during the accident and to an earlier failure of the cladding than when the effect of nitrogen reactions was not considered. It should be noted that the nitriding model, as implemented in the PSI version of MELCOR 1.8.6 has not yet been conclusively validated. Thereby the results presented in this paper should be treated as a preliminary demonstration of the capabilities of the model.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.299-306
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• 2002

The purpose of this research was to develop a rapid setting cement latex modified concrete (RSLMC) for bridge deck repairing and overlaying. The main experimental variables were latex contents, antifoamer contents and water-cement ratioes. The workability, strength development and permeability were measured as responses. The results showed that latex content increased the slump and reduced the unit water required for same workability. The air contents were measured as 8.0∼9.0％ and 2.0∼3.0％ without antifoamer and with 1.6∼3.2％ of antifoamer, respectively. This resulted in the increment of compressive strength development by 10∼20 ％. The flexural strength of RSLMC increased greatly as the latex content increased, but not in compressive strength. The compressive strength and flexural strength developed enough for opening the overlayed RSLMC to the traffic after 3 hours of RSLMC placement. The permeability of RSLMC was evaluated as negligible due to its very low charge passed. Thus, RSLMC could be used at repairing or overlaying the concrete bridge deck at fast-track job sites.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.4
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• pp.445-451
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• 2019

In this study, we evaluated the durability of concrete produced with recycled polymer that could replace synthetic polymer, which is the main raw material of bridge deck concrete pavement. As a result of the slump and air content test, the requirements of the Korea Highway Corporation Standard were satisfied with all mixing conditions. The slump was lowered when incorporating the recycled bio-polymer, compared to other mix proportions concrete. In contrast, the compressive strength was increased by 6.3~24.4% when the recycled bio-polymer was mixed, compared to the concrete produced with synthetic polymer. It should be noted that the compressive strength was lowered when synthetic polymer was added to concrete mixture. Durability test results showed the best durability when incorporating synthetic polymer. The durability of concrete also increased as the amount of recycled bio-polymer increased, however, the impact was slightly smaller than that of synthetic polymer.

• Journal of the Korean Society of Systems Engineering
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• v.11 no.1
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• pp.33-39
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• 2015

This paper describes a development of aircraft carrier aviation support system architecture using DoDAF. The aircraft carrier, a warship performing a role of mobile sea air base in offensive and defense mission, is super system that is comprised of carrier itself and carrier-based airwing. Performing critical role in step with aviation operations in carrier-airwing interactions, the aviation support system of aircraft carrier is also system of systems. It requires a complex and integrated approach based on systems engineering in establishing concept of this complex systems. In this view, this study establishes an operational scenario and derives operational requirements by identifying aviation operations environment on deck of aircraft carrier. The study presents the operational architecture of the carrier aviation support system by using DoDAF and CASE tool CORE.