• Journal of the Korean Society for Heat Treatment
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• v.8 no.3
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• pp.182-186
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• 1995

SCM440, which is widely used as the diesel engine piston of vessel, has been hardened by a $CO_2$ laser with the wavelength of $10.6{\mu}m$. Laser hardening experiment has been carried out for the condition of a laser power 1kW, the travel speed between 0.4 and 1.5m/min, and a rectangular-Gaussian beam. Residual stress has been measured by using middle point technique of half value width of X-ray diffraction method. It was found that the compressive residual stress with the range between 400 and 600MHz has distributed in the laser hardening zones and the tensile residual stress between 100 and 200MHz has distributed in the boundary of hardening zones.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.454-459
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• 2001

The present study is concerned with the flow patterns induced by other impellers in a rectangular tank Impellers are FBT(Flat blade turbine), PBT(Pitched blade turbine), Shroud turbine, Rushton Turbine, and Helical ribbon turbine. The solution of flows in moving reference frames requires the use of 'moving' cell zone. The moving zone approaches are MRF(Multiple reference frame), which is a steady-state approximation and Sliding method, which is a unsteady-state approximation. Numerical results using two moving zone approaches are compared with experiments by Ranade & Joshi, which have done extensive LDA measurements of the flow generated by a standard six-bladed Rushton turbine in a cylindrical baffled vessel. In this paper we simulated the flow patterns with above mentioned moving zone approaches and impellers. Turbulence model is RNG k-$\epsilon$ model.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.5
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• pp.68-75
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• 1996

The vacuum drying characteristics of water-saturated porous media were studied experimentally. The water-saturated porous media, water-saturated sand layer, was heated by the isothermal bottom wall of the rectangular vessel. The vacuum drying rate and temperature distribution of the sand layer were measured and calculated under a variety of conditions of heated wall temperature, vacuum rate, and thickness of the test material. It was found that the drying rate due to the heat and mass teansfer is greatly influenced by the heated wall temperature, vacuum rate, and thickness of the test material.

• Journal of Ship and Ocean Technology
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• v.7 no.1
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• pp.29-35
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• 2003

Intensive experimental investigation has been conducted on the characteristics of model tank with intruded flow. The remaining flow inside tank contribute to the dynamic behavior and further closely related to the stability of vessel as well. To understand the importance of the trapped flow and its dynamic effects a series of systematic tests were conducted using a bench tester that could generate periodic roll motion and also complex motions of combined roll-heave-sway. To accommodate experimental conditions and to create three degree freedom of motions, a bench tester was fabricated and verified. Having similarities in terms of flow trapped inside tank, theoretical approaches for A.R.T. were applied to the study. The major parameters including roll angle, period and flow height were varied in the experiments to obtain the characteristics of model tank.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.5
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• pp.435-444
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• 2011

This paper deals with the structural assessment of metallic and non-metallic stiffened/monocoque plated marine structures under a lateral pressure load to identify appropriate combination of material and section configuration, especially at the preliminary marine structural design stage. A generic rectangular plated structure is exemplified from the metallic superstructure of a marine vessel and its structural topology is varied for the structural assessment. In total 13 different structural topologies are proposed and assessed using appropriate elastic solutions in conjunction with a set of stress and deflection limits obtained from practice. The geometry dimensions and weights of the structural topologies are calculated, and subsequently, the costs of the materials used in the structural topologies are reviewed to discuss the cost-effectiveness of the materials. Finally, conclusions are made with the aim of suggesting suitable structural topology for the marine structural member considered in this paper.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.5
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• pp.1472-1478
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• 1991

본 연구에서는 Rectangular Computer Tension(CT) 시편을 수정하여 만든 표준 시편인 MRL-CLWL시편(material research laboratorycrack line wedge loaded specimen )으로 균열정지 인성치를 결정하였다. 그리고 CT시편과 같은 효과를 갖는 Newman등 이 제안한 round compact tension(RCT)시편을 수정한 Round-CLWL 시편으로 균열정지인 성치를 결정하여 상호 비교평가하였다. Round-CLWL 시편은 시편제작시 round-bar를 절단하여 시편으로 가공할 수 있으므로 가공성이 좋으며 따라서 가공비가 적게 든다. 특히 균열 위치 및 방향을 임의로 선택하여 가공하기가 용이하므로 방향성이 있는 소 재의 균열정지 인성치를 결정하는 데 매우 편리한 시편이라 생각된다. 본 논문에서 는 Round-CLWL 시편으로 $K_{1a}$ 값을 계산하는데 필요한 형상계수를 결정하였으며, Polymethylmethacrylate(PMMA)를 사용하여 Round-CLWL 시편 채택의 타당성 확인을 위 한 MRL-CLWL과 Round-CLWL 시편 채택의 타당성 확인을 위한 MRL-CLWL과 Round-CLWL시 편의 $K_{1a}$결정 실험을 하였다.하였다.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.3
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• pp.359-363
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• 2011

An orthogonal magnetic field is often used for a military vessel in the deperm process such as Flash D deperm protocol and Anhysteretic deperm protocol. The effect of the orthogonal magnetic field on a deperm performance was investigated for a sample with strain-induced magnetization and field-induced magnetization given to different direction. A 70mm wide, 110mm long and 0.25mm thick rectangular steel plate was bent to have U-shape and to generate a strong strain on the bottom region of U-shaped steel plate. Field-induced magnetization was attached by NdFeB permanent magnet. Demagnetization was performed by applying magnetic field with a step decrement from the first field(the first shot) under the action of DC bias field.

• Journal of the Korean Institute of Gas
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• v.11 no.2 s.35
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• pp.37-42
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• 2007

This paper presents the leakage safety of two O-rings, which are located at the rectangular groove between a valve body and a valve stem. The leakage safety analysis of 0-ring seals has been computed as functions of a compression set and a liquefied petroleum gas pressure of a LPG cylinder using a FEM program, MARC. The FEM computed results indicate that the loads from the filling pressure of $8kg/cm^2$ to the upper limit of the safety valve, $24.8kg/cm^2$ work safely according to the pressure vessel code. But two O-rings should consider the aging effects for an increased safety of the o-ring.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3491-3496
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• 2007

If a molten core is released from a reactor vessel into a reactor cavity during a severe accident, an important safety issue of coolability of the molten core from top-flooding and concrete ablation due to a molten core concrete interaction (MCCI) is still unresolved. The released molten core debris would attack the concrete wall and basemat of the reactor cavity, which will lead to inevitable concrete decompositions and possible radiological releases. In a OECD/MCCI project scheduled for 4 years from 2002. 1 to 2005. 12, a series of tests were performed to secure the data for cooling the molten core spread out at the reactor cavity and for the 2-D long-term core concrete interaction (CCI). The tests included not only separate effect tests such as a melt eruption, water ingression, and crust failure tests with a prototypic material but also 2-D CCI tests with a prototypic material under dry and flooded cavity conditions. The paper deals with the transient simulations on the CCI-2 test by using a severe accident analysis code, CORQUENCH, which was developed at Argonne National Laboratory (ANL). Similar simulations had been already per for me d by using MELCOR 1.8.5 code. Unlike the MELCOR 1.8.5, the CORQUENCH includes a melt eruption mode I and a newly developed water ingression model based on the water ingression tests under the OECD/MCCI project. In order to adjust the geometrical differences between the CCI-2 test (rectangular geometry) and the simulations (cylindrical geometry), the same scaling methodology as used in the MELCOR simulation was applied. For the direct comparison of the simulation results, the same inputs for the MELCOR simulation were used. The simulation results were compared with the previous results by using MELCOR 1.8.5.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.5
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• pp.695-699
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• 2003

Traditional soybean sprouting bucket has some problems which are putrefaction and growing inhibition by the high temperature and carbon dioxide in the bucket during culturing. To solve this problems we developed the new soybean sprouting bucket. The new bucket consisted a square shaped bottom which has 5 draining holes (each 10 mm in dia, 2 mm in height) and four side wall which has two rectangular shaped holes (10 cm long, 0.5 cm wide), and the support vessel which 592 tiny draining holes whose center attached a pipe with 36 small holes (each 2 mm in dia). The new one showed lower temperature and carbon dioxide content during culturing, and the putrefaction was lower, whereas growing degree was higher during culturing at 25$\pm$1$^{\circ}C$ than the traditional bucket.