• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.2
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• pp.169-177
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• 2020

Here, the stability of stainless steel 316 (SS-316) was investigated to identify its applicability in the oxide reduction process, as a component in related equipment, to produce a complicated gas mixture composed of O₂ and Cl₂ under an argon (Ar) atmosphere. The effects of the mixed gas composition were investigated at flow rates of 30 mL/min O₂, 20 mL/min O₂ + 10 mL/min Cl₂, 10 mL/min O₂ + 20 mL/min Cl₂, and 30 mL/min Cl₂, each at 600℃, during a constant argon flow rate of 170 mL/min. It was found that the corrosion of SS-316 by the chlorine gas was suppressed by the presence of oxygen, while the reaction proceeded linearly with the reaction time regardless of gas composition. Surface observation results revealed an uneven surface with circular pits in the samples that were fed mixed gases. Thermodynamic calculations proposed the combination of Fe and Ni chlorination reactions as an explanation for this pit formation phenomenon. An exponential increase in the corrosion rate was observed with an increase in the reaction temperature in a range of 300 ~ 600℃ under a flow of 30 mL/min Cl₂ + 170 mL/min Ar.

• International Journal of Fluid Machinery and Systems
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• v.9 no.3
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• pp.256-264
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• 2016

To meet the demand of higher handling capacity, a mixed-flow submersible deep well pump was designed and tested. The main hydraulic components are made of plastics, which is free of erosion, light-weight, and environment-friendly. To simplify plastic molding process, and to improve productivity, an axial-radial guide vane was proposed. To clarify its effect on the performance, a radial guide vane and a space guide vane are developed as well. By comparison, the efficiency of the pump equipped with the axial-radial guide vane is higher than the radial guide vane and is lower than the space guide vane, and its high efficiency range is wide. The static pressure recovery of the axial guide vane is a bit lower than the space guide vane, but it is much larger than the radial guide vane. Taking the cost and molding complexity into consideration, the axial-radial guide vane is much economic, promoting its popularity for the moderate and high specific speed submersible deep well pumps.

• Journal of the Korean Solar Energy Society
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• v.27 no.2
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• pp.79-85
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• 2007

The performance of in-line duct fan depends on the design parameters of impeller and guide vane such as sweep back angle of impeller hub, guide vane angle etc. In this study four kinds of impellers having different sweep back angles, $0^{\circ}$, $17.5^{\circ}$, $35^{\circ}$, $52.5^{\circ}$ with 8 guide vanes, and different guide vane angles, $15^{\circ}$, $30^{\circ}$, $45^{\circ}$ were selected and their performance measured to investigate the effects of design parameters. The results show that both sweep back angle of impeller hub and the guide vane angle have large effect on the efficiency. Especially, it was found that the mixed flow impellers having sweep back angle between $17.5^{\circ}$ and $35^{\circ}$ gave good performances for in-line duct fan.

• Journal of Power System Engineering
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• v.10 no.4
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• pp.71-77
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• 2006

This study introduces the seismic qualification of safety related equipments for nuclear power plants to verify the possibility of resonance in regard to the operating speed and the structural integrity due to external piping nozzle loads as well as seismic dynamic loads using El-Centro earthquake, which was occurred in the 1940's previously. As a first step, it is necessary to investigate the natural frequency of the vertical mixed flow pump in order to determine whether static or dynamic equipment comparing with seismic cut-off frequency, 33hz. Also the normal mode analysis was carried out with the introduction of seismic redesign straint at the middle of vertical pump to increase the natural frequency. In terms of structural integrity, the application of static analysis with normal, upset and faulted nozzle loads event was presented for the comparison of material allowable stress. Also the dynamic analysis was performed to show the design adequacy through the application to the case of El-Centro earthquake.

• Advances in concrete construction
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• v.15 no.4
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• pp.241-249
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• 2023

The unsteady mixed convection Casson type MHD nanofluid flow in the stagnation point with motile microorganism around a spinning sphere is investigated. Time dependent flow dynamics is considered. Similarity transformations have been employed to transfer the governing partial differential structure into ordinary differential structure. The impact of distinct parameters is examined via tables and graphs. The impact of rotational parameter (spin) on profiles of velocity profiles, temperature and concentration is revealed for unsteady mixed convection Casson type MHD nanofluid flow. It is observed that it is clear that rotational parameter has a great effect on non-dimensional primary velocity component but rotational parameter has a slight impact on non-dimensional secondary velocity component. The validity of the current investigation is authorized through comparing the existing outcomes with previous published literature.

• Journal of Korea Multimedia Society
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• v.21 no.8
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• pp.829-836
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• 2018

This study attempts to detect a shot boundary in films(or dramas) based on the length of a sequence. As films or dramas use scene change effects a lot, the issues regarding the effects are more diverse than those used in surveillance cameras, sports videos, medical care and security. Visual techniques used in films are focused on the human sense of aesthetic therefore, it is difficult to solve the errors in shot boundary detection with the method employed in surveillance cameras. In order to define the errors arisen from the scene change effects between the images and resolve those issues, the mixed algorithm based upon color histogram, edge histogram, and optical flow was implemented. The shot boundary data from this study will be used when analysing the configuration of meaningful shots in sequences in the future.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.11 no.1
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• pp.57-70
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• 2007

The effects of variable viscosity, blowing or suction on mixed convection flow of a viscous incompressible fluid past a semi-infinite horizontal flat plate aligned parallel to a uniform free stream in the presence of the wall temperature distribution inversely proportional to the square root of the distance from the leading edge have been investigated. The equations governing the flow are transformed into a system of coupled non-linear ordinary differential equations by using similarity variables. The similarity equations have been solved numerically. The effect of the viscosity temperature parameter, the buoyancy parameter and the blowing or suction parameter on the velocity and temperature profiles as well as on the skin-friction coefficient and the Nusselt number are discussed.

• Journal of the Korean Society of Food Culture
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• v.10 no.3
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• pp.167-174
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• 1995

A hazard analysis which included watching operations, measuring temperatures of foods throughout preparation and display, and sampling and testing for microorganisms of total plate counts and coliform bacteria was conducted in various phases of product flow of Naeng-myeun (Cold noodles) and Pi-bim bab (mixed rice) prepared at Korean restaurants. Large numbers of total plate counts were counted from the cooked foods after handling and holding. Ingestion of these foods must be considered high risk. Critical control points identified were, pre-preparation, food handling after cooking, and holding on display in product flow of Nang-Meon and pre-preparation, preparation, and holding on display in product flow of Pi-bim bab. It need for effective quality control of Nang-Meon and Pi-bim bab that training program consist of surveillance, education of the staff, standard operation procedures, forbidding dangerous processes and control of critical points.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1996.05a
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• pp.197-205
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• 1996

A combined extrusion process studied here consists of forward and backward extrusion, and it is formed in single operation. The metal flow involved in the operation has appeared to be difficult to analyze accurately because of mixed directions of the flow. In this study, conventional two operations of a forward and a backward extrusions is transformed into one operation of mixed extrusion. A process designed by an industry expert is simulated by the rigid-plastic finite element method to investigate the metal flow and defects. In addition to the FEM simulation, experimental analysis has been carried out to confirm the design in industry, which includes material characterization, preliminary expriment, and whole experimental forming operation. The experimental results show that warm forming of extrusion is more desirable than cold working and hot forming in view of grain growth. Also two conditions of lubrication between workpiece and die has been investigated.

• Journal of Magnetics
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• v.21 no.1
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• pp.153-158
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• 2016

This paper aims to discuss the Non Darcy boundary layer flow of non-conducting viscous fluid with magnetic ferroparticles over a permeable linearly stretching surface with ohmic dissipation and mixed convective heat transfer. A magnetic dipole is applied "a" distance below the surface of stretching sheet. The governing equations are modeled. Similarity transformation is used to convert the system of partial differential equations to a system of non-linear but ordinary differential equations. The ODEs are solved numerically. The effects of sundry parameters on the flow properties like velocity, pressure, skin-friction coefficient and Nusselt number are presented. It is deduced the frictional resistance of Lorentz force decreases with stronger electric field and the trend reverses for temperature. Skin friction coefficient increase with increase in ferromagnetic interaction parameter. Whereas, Nusselt number decrease.