• Journal of Korea Ship Safrty Technology Authority
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• s.31
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• pp.60-70
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• 2011

The slamming impact pressures at the bottom area of the Open60' are evaluated by the rules and regulations of various organizations - ISO and classification societies. The enhanced performance of the modern racing yacht in terms of speed which achieves well over 20 knots needs special consideration. The calculated design impact pressures are compared a experimental results. Severe difference can be found in these calculation results but the final conclusion shall be obtained after the scantling calculation under the evaluated design impact pressure so far.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.408-413
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• 2004

High speed planning boats also have been required more and more the rational strength analysis and evaluation for the optimal structural design in respect of the structural lightness according to the high speed trend. Even though the suggestion of the simple type equation for the equivalent dynamic pressure is reasonable to design the scantling of ship structure conveniently, many research activities for more reasonable improvement of the simple design pressure, have been continued to suggest the more accurate equivalent static description of tire structural response such as the deflection and stress of hull structure. In this research, we focus on the aluminum bottom stiffened plate structure in which structural scantling is mainly depend on the local loads such as dynamic or impact pressure without other load effects and structural response for the simple dynamic equivalent pressure was investigated through the structural analysis. In order to investigate the structural response of the bottom stiffened plate structure subjected to the dynamic equivalent design pressure, linear and nonlinear structural analysis of the bottom stiffened plate structure of 4.3 ton aluminum planning boat was performed based on the equivalent static applied loads which were derived from the KR regulation and representative one among various dynamic equivalent pressure equations. From above analysis results, we found that the response such as deflection and stress of plate member was similar with the response results of one plate member model with fixed boundary, which was published previous paper and in case of KR design loading, all response of stiffened plate structure were within elastic limit. Through the nonlinear analysis, nearly elastic behavior including the slight geometrical nonlinear response was dominant but plastic local zone was appeared at $85\%$ limit load. Therefore, we can say that through tire linear and nonlinear analysis, this stiffened plate member has no structural strength problem based on the yield criteria in case within $60\%$ limit load except the other strength point of view such as the fatigue and buckling problem.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1109-1110
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• 2013

• Magazine of the Korean Society of Agricultural Engineers
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• v.14 no.1
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• pp.2557-2569
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• 1972

Hydraulic computations to determine the elevation of canal bottom and mater surface for box type concrete culverts are discussed. Velocity and cross sectional area of flow are computed from Manning's formula. Aad then head loss and velocity head are considered to determine the elevation of bottom and water surface. For stress analysis, 13.5 ton live load and earth pressure are considered. Also longitudinal stress of box culverts is checked.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.107-109
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• 2014

Through the economic development, people enjoying the camping and demand of camping goods are increasing since they have free time. So they use portable butane gas range outdoor. In addition to that, many restaurants that offer hotpot or meat in Korea use portable butane gas ranges for their convenience. But 19% of gas accidents are using portable butane gas range, 13.7% of them are using oversized cookware. Despite the high accident rate, there is no safety standards about portable butane gas range using oversized cookware. Therefore we conducted to measure temperature and pressure of portable butane gas ranges for reforming safety standards. As a result. we confirmed relation between bottom temperature of the portable butane gas barrel and pressure of the butane gas. Also we confirmed that portable butane gas ranges operate safely when bottom temperature of the portable butane gas barrel is bellow $50^{\circ}C$.

• Geomechanics and Engineering
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• v.1 no.3
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• pp.179-191
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• 2009

For a two-way drainage deposit under a surcharge load, it is possible to leave a layer adjacent to the bottom drainage boundary without prefabricated vertical drain (PVD) improvement and achieve approximately the same degree of consolidation as a fully penetrated case. This depth is designated as an optimum PVD installation depth. Further, for a two-way drainage deposit under vacuum pressure, if the PVDs are fully penetrated through the deposit, the vacuum pressure will leak through the bottom drainage boundary. In this case, the PVDs have to be partially penetrated, and there is an optimum installation depth. The equations for calculating these optimum installation depths are presented, and the usefulness of the equations is studied by using finite element analysis as well as laboratory model test results.

• Bulletin of the Society of Naval Architects of Korea
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• v.15 no.3
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• pp.1-7
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• 1978

The dynamic pressures on the bottom of high speed small crafts are studied. Using the dynamic load factor the dynamic pressure can be replaced by equivalent static pressure. Assuming that (1) the system is undamped with a single degree of freedom and (2) the load is applied triangularly, we obtained the max, value of the dynamic load factor of 1.455. We believe that this method could provide a guide to the designer who has no data on the craft in the preliminary structural design stage.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.1
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• pp.26-29
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• 2006

Transparent ZnO thin films were prepared by KrF pulsed laser deposition (PLD) technique and applied to a bottom-gate type thin film transistor device as an active channel layer. A high conductive crystalline Si substrate was used as an metal-like bottom gate and SiN insulating layer was then deposited by LPCVD(low pressure chemical vapour deposition). An aluminum layer was then vacuum evaporated and patterned to form a source/drain metal contact. Oxygen partial pressure and substrate temperature were varied during the ZnO PLD deposition process and their influence on the thin film properties were investigated by X-ray diffraction(XRD) and Hall-van der Pauw method. Optical transparency of the ZnO thin film was analyzed by UV-visible phometer. The resulting ZnO-TFT devices showed an on-off ration of $10^6$ and field effect mobility of 2.4-6.1 $cm^2/V{\cdot}s$.

• Journal of the Korean Geotechnical Society
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• v.27 no.2
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• pp.27-34
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• 2011

This study analyzes the determination of slope failure model due to changes in ground condition followed by heavy rainfall. With a simulated rainfall system, the movement of a slope from the rainfall penetrating the unsaturated soil is investigated with respect to various conditions of pore-water pressure, earth pressure, and moisture content, considering rainfall duration and permeability. As a result of the experiment, under the persistent precipitation of 50mm/h, pore-water pressure of weathered granite soil started increasing from the upper position of the slope, and then the pressure increased in middle and bottom portion of it in timely manner. In case of the pore-water pressure of the standard soil, the pressure increased from the middle and bottom portion, and the cause of the different order is suspected to be the difference in permeability between the standard soil and the weathered granite soil. As an outcome, though the result may vary by each foundation, there exists a danger of slope failure not only when the cumulative rainfall is more than 120 mm but also when the saturation level amounts to 60~75%.

• Geotechnical Engineering
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• v.12 no.5
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• pp.27-40
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• 1996

Box culvert has long since been used for various purposes , water and sewerage works, communication and electricity facilities, subway, railway, etc. In urban area, the construetion of box culvert generally consists of excavation-installation of the culvert-backfill. However, the existing design methods for earth pressure on the box culvert do not take into account the excavation(or backfill) geometry. ' A new method considering excavation geometry for earth pressure on box culvert is suggested here. The lateral earth pressures by the newly suggested method agree relatively with results of finite element analyses, but those of existing method are greatly overestimated. The vertical pressure on the top of the box culvert by the new method is similar to those of existing method and finite element analysis. However, the reactional pressure on the bottom of the box culvert depends largely upon the stiffness of the foundation soil. The reactional pressure by the new method agrees well with that of finite element analysis, only when the stiffness is low. From the finite element analysis it is shown that the lateral earth pressure on box culvert depends upon the excavated slope (G) and the net bottom distance (Bc).