• Journal of Mechanical Science and Technology
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• v.20 no.10
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• pp.1773-1778
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• 2006

Steady-state natural convection heat transfer characteristics from cylinders in a multiply-connected bounded region are clarified. A spectral finite difference scheme (spectral decomposition of the system of partial differential equations, semi-implicit time integration) is applied in numerical analysis, with a boundary-fitted conformal coordinate system through a Jacobian elliptic function with a successive transformation to formulate a system of governing equations in terms of a stream function, vorticity and temperature. Multiplicity of the domain is expressed explicitly.

• ETRI Journal
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• v.32 no.2
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• pp.195-203
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• 2010

A new vertical transition between a substrate integrated waveguide in a low-temperature co-fired ceramic substrate and an air-filled standard waveguide is proposed in this paper. A rectangular cavity resonator with closely spaced metallic vias is designed to connect the substrate integrated waveguide to the standard air-filled waveguide. Physical characteristics of an air-filled WR-22 to WR-22 transition are compared with those of the proposed transition. Simulation and experiment demonstrate that the proposed transition shows a -1.3 dB insertion loss and 6.2 GHz bandwidth with a 10 dB return loss for the back-to-back module. A 40 GHz low-temperature co-fired ceramic module with the proposed vertical transition is also implemented. The implemented module is very compact, measuring 57 mm ${\times}$ 28 mm ${\times}$ 3.3 mm.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1478-1485
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• 1993

A shape optimization problem is formulated to determine the optimal position of heating lines in a compression molding die. The objective of the problem is that the cavity surface would be maintained by a prescribed uniform temperature. A boundary integral equation for the sensitivity of the temperature in terms of hole position is derived using the method of shape design sensitivity analysis. The boundary element method is employed to analyze the temperature and sensitivity field of the die. The sensitivity calculation algorithm is incorporated in an optimization routine. To demonstrate a numerical implementation, an example problem arising in thermal design of a compression molding die is dealt with, showing that the number of heating lines chosen for the die strongly affects the ultimate uniformity of the cavity surface temperature.

• Journal of the Korean Geotechnical Society
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• v.39 no.7
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• pp.69-76
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• 2023

Cavity causes settlement and its remediation after an accident results in significant time and economic losses. This study aims to experimentally evaluate the prospect of using infrared camera to detect and measure underground subsidence. Emissivity is necessary to detect the energy emitted from an object and accurately assess temperature using an infrared camera. The emissivity in laboratory tests is fixed to evaluate a reasonable distance between the infrared camera and the object, and temperature values are assessed at various distances. In field experiments, the cavity of the field experiment is simulated using a PVC pipe with a diameter of 5 cm, artificially buried at depths of 5 and 25 cm from the surface. The infrared camera measurements are taken from 4 PM to 3 PM of the next day (a total of 23 h). The analysis included the time-series temperature distribution and the cooling rate index assessment, which represents the temperature change rate per unit of time. The results showed that various temperature trends are observed depending on the location of the subsidence. This study demonstrates that the infrared camera can be used to assess the condition of the subsurface.

• The Journal of Internal Korean Medicine
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• v.1 no.1
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• pp.56-63
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• 1976

The results of the So Shi Ho Decoction efficacy on the Salmonellatyphi (Ty 2) of the rabbits (2.5kg) in the fever cases were as follows: 1. The range of the rabbit's temperature was from $38.8^{\circ}C$ to $39.8^{\circ}C$ 2. Average temperature of rabbits were increased $2.35^{\circ}C$ from $39.35^{\circ}C,$ 48 hours after $10^6/ml,\;10^4/ml$ of the Salmonella typhi (Ty 2) were injected into the abdominal cavity of rabbits. $10^2/ml$ of the Salmonella typhi (Ty 2) were injected into the abdominal cavity of the rabbits, the body temperature was increased from $39.8^{\circ}C$ to $40.6^{\circ}C.$ 3. There was some elevated and kept the normal temperature of rabbits by the into the abdominal cavity of the rabbits, the body temperature was increased from $39.8^{\circ}C$ to $40.6^{\circ}C.$ 4. There was some elevated and kept the normal temperature of rabbits by the So Shi Ho decoction of 10ml after injection of the Samonella typhi (Ty 2) of $10^6/ml.$ Before the administration of So Shi Ho decoction, the rabbits temperature was elevated from $39.43^{\circ}C$ to $40.1^{\circ}C$ after 24 hours, and was brought down from $39.43^{\circ}C$ to $39.4^{\circ}C$ after 72 hours of So Shi Ho decoction administration. 5. The rabbit's temperature was elevated by administration the Salmonella typhi (Ty 2) through the mouth. The average rabbit's temperature were elevated from $39.43^{\circ}C$ to $39.6^{\circ}C,\;39.73^{\circ}C,\;40.01^{\circ}C$ and $40.07^{\circ}C,$ there was no visible change. 6. The rabbit's temperature was elevated from $39.43^{\circ}C$ to $40.03^{\circ}C$ after 24 hours, and was brought down from $39.43^{\circ}C$ to $39.37^{\circ}C$ after 72 hours of So Shi Ho decoction administration. 7. Above the results, we could find the some sedative action of the So Shi Ho decoction efficacy on the Samonella typhi (Ty 2) of the rabbits in the fever cases.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.401-404
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• 2008

In the present investigation, a high precision thermal imprint system for micro ceramic products was developed and the net-shape manufacturing of multi-layer ceramic reflector for LED (Light Emitting Diode) was conducted with a precision metal die. Workpiece used in the present investigation were the multi-layer laminated ceramic sheets with pre-punched holes. The cavity with arbitrary angle was formed on the circular and rectangular holes of the ceramic sheets. During the imprinting process, the ambient temperature of the imprint system was kept over the transition temperature of the ceramic sheet and then rapidly cooled. The results in this paper show that the present method can be successfully applied to the fabrication of very small size hole array for ceramic reflector in a one step operation.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.509-515
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• 2001

In a square cavity, the flow phenomena in the surrounding of the bubble attached at the upper cooled solid wall were studied by using a thermo-sensitive liquid-crystal tracer and image processing techniques. This method offers the advantage of measuring the entire flow field in a selected plane within the fluid at a given instant of time in contrast to point by point method like T/C. Quantitative data of the temperature were obtained by applying a colour-image-processing to the. visualized image. As the growing of a bubble, In a bubble size appears the flow phenomena which the direction of flow is reversed in the entire temperature and flow field. The observed phenomena are described with regard to thermocapillary convection.

• Tribology and Lubricants
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• v.13 no.1
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• pp.70-75
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• 1997

The lubrication characteristics of high-speed ball bearings at oil-starvation have been investigated empirically using the bearings employed in small industrial gas turbine engines. For the close structural simulation, experiments carried our with bearing mounting supports of real engines, such as bearing housings and oil nozzle assemblies with squeeze film dampers. Thus the results of tests can be applied to the design and the development of gas turbine engines. Testing was done by simulating the oil-starvation conditions in engines, such as stopping the oil-supply to the bearing during normal operating, starting without oil-supply at atmospheric temperature, and accelerating with oil-supply at atmospheric temperature. From this study, the relative comparison of the frictional resistance and the resistance due to the bearing cavity oil was demonstrated visually, and the resistance due to the bearing cavity oil was dominant in the resistance of bearing at high speed.

• Journal of Mechanical Science and Technology
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• v.15 no.6
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• pp.796-803
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• 2001

Numerical solutions for the convection-dominated melting in a rectangular cavity are presented. The enthalpy-porosity model is employed as the mathematical model. This model is applied in conjunction with the EIT method to detect boundary movement in a phase changing environment. The absorption and evolution of latent heat during the phase change is dealt with by the enthalpy-based energy equation. This seems to be more efficient than resolving the temperature-based energy equation. The velocity switch-off, which is required when solid changes into liquid, is modeled by the porous medium assumption. For efficiency and simplicity of the solutions procedure, this paper proposes a simple algorithm, which iterates the temperature and the liquid fraction of the cells comprising the front layer. The numerical results agree reasonably well with the experimental data and other previous works using the transformed-grid system.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.230-233
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• 2006

In this study, the effects of residual stress induced by plastic injection molding process on the tensile behavior of plastic tensile test specimen were investigated. To manufacture plastic tensile test specimens, an injection mold based on the international standard system was designed and made. Cavity pressure and temperature sensors were installed inside of the presented mold to monitor pressure and temperature values during the cycle of injection molding. Injection molding simulation was performed with the same condition of experiment and linear structural tensile analysis was also performed with the initial condition of the residual stress. It was shown that the residual stress induced by injection molding has an effect on the experiment of tensile test and linear structural tensile simulation.