• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.543-548
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• 2006

This paper is to be researched into ozone generation character of Bi-Ti-Si type high dielectric ceramic catalyst discharge tube. And conditions of basic experiment are the outside diameter of discharge tube : 52 mm, the length of discharge tube : 350 mm, the frequence : 900 Hz, the temperature of cooling water : $25^{\circ}C$, quantity of flow : 5, 10, 20 L/min, pressure : 1.2, 1.4, 1.6 atm, and distance of discharge gap : 0.4, 0.6, 0.8 mm. Ozone generation characteristics were measured to consumption power. At quantity of flow : 20 L/min, discharge gap : 0.6 mm, pressure : 1.6, and consumption power : 150 W, Maximum ozone generation efficiency of 175 g/kWh was obtained. And a range of maximum ozone generation efficiency was measured below the flow quantity of 20 L/min at below pressure of 1.6 atm. However, Maximum ozone generation efficiency was measured over the flow quantity of 20 L/min at over pressure of 1.6 atm.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.7
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• pp.581-588
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• 2014

The inlet/outlet flow in the tube-side of the shell and tube heat exchanger was experimentally measured to investigate the effect of the porous baffle on uniform flow distribution. A 1/3rd scale-downed model of a heat exchanger was used and particle image velocimetry was applied for measuring the instantaneous velocity vector fields. The absolute errors in the flow rate were calculated and compared for the tube-side with and without the porous baffle, by varying the flow rate from 60 to 90 LPM. The results revealed that the porous baffle can improve flow uniformity and reduce the absolute error in the flow rate of the model with the baffle by about 74%, compared to that without the baffle. This result can be used for improving the performance and design of the shell and tube heat exchanger.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.5
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• pp.321-328
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• 2017

In this study, vortex tube system model is developed to predict the temperature of the hot and the cold sides. The vortex tube model is developed based on the system identification method, and the model utilized in this work to design the vortex tube is ARX type (Auto-Regressive with eXtra inputs). The derived polynomial model is validated against experimental data to verify the overall model accuracy. It is also shown that the derived model passes the stability test. It is confirmed that the derived model closely mimics the physical behavior of the vortex tube from both the static and dynamic numerical experiments by changing the angles of the low-temperature side throttle valve, clearly showing temperature separation. These results imply that the system identification based modeling can be a promising approach for the prediction of complex physical systems, including the vortex tube.

• Journal of Veterinary Clinics
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• v.26 no.5
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• pp.467-471
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• 2009

This report describes Neural Tube Defects (NTDs) with Abdominal Wall Defects (AWDs) on the sibling of Yorkshire terriers. The NTDs and AWDs are rare serious congenital defects. The NTDs are neurulation abnormality that results from to failed transformation of the neurual tube by the incomplete closure of the embryonic neural plate. These dysraphic states range form mild to severe according to developmental malformation that include fusion defects of skull (crania bifida; CB) and fusion defects of vertebrae (spina bifida; SB). The AWDs are genetic defects that results from to failed formation of abdominal wall and cavity. These dysraphic states are omphalocele and gastroschisis. The 12-month dam was delivered by caesarian section and 4 littermate had obvious malformations. One male dead stillbirth fetus (L1) was revealed the extruded abdominal viscera, omphalocele. One female fetus (L2) was died within 1 hour after birth with defects of abdominal muscle upper umbilicus, gastroschisis. 3rd fetus (L3) was died within 36 hours after parturition and revealed a copious dermal and vertebral defects on the midline thorax, upper SB asperta. 4th fetus (L4) is still growing well now at 6 months but at the 2 week age, appears hairy nevus on the frontal cranium and dorsal thoracic portion. The radiograph of L1 and L2 are shown decrease bony density of calvarium and L3 was shown defect of spinose processes of the T9-T13. On our knowledge, this is first report of the SB and CB in Yorkshire terrier. And also sibling of NTDs with AWDs that has not previously been reported in the dog.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.3 no.2
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• pp.125-130
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• 1993

We has made 2-zone vertical electric furnace and has been grown CdS single crystal by sublimation method in crystal growth tube with tail tube without seed crystal for growth. While it has been growing, temperature difference ${\Delta}T$ of source and growth part has nearly agreed with theoritical value $14.7^{\circ}C$and experimental value $15^{\circ}C$ Then, crystal of best quality has been grown, when temperature of tail tube has been $110^{\circ}C$, in spite of quickly pulling up crystal growth tube a degree O.38mm per hour. The grown crystal have had hexagonal structure and single crystal with c-axis to length of crystal growth tube from X- ray diffraction pattern of powder method and Laue pattern of back reflection Laue method. Also, the mobility and carrier density from Hall effect measurement have been $316cm^2/V{\cdot}sec$ and $2.90{\times}10^{16}cm^{-3}$ at the room temperature, respectively.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.2
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• pp.187-193
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• 2015

The STS310S tube has excellent heat transfer ability and is widely used as the material for heat transfer tubes in heat exchange devices. Mixtures of gas and water flow inside the tube whereas hot flame flows outside it. In this environment, the material of the tube may undergo embrittlement, which can cause leakage. Cracks can propagate from the inside of the tube to its outside and result in brittle fracture. This study identified the cause of brittle fracture in the STS310S tube through experiments and discussion, and proposed solutions to prevent fracture.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1377-1380
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• 2008

An irradiation test of a nuclear fuel rod having external and internal tube structure was planned for a performance. To establish fabrication process satisfying the requirements of irradiation test, micro-TIG welding system for fuel rods was developed, and preliminary welding experiments for optimizing process conditions of fuel rod was performed. Fuel rods with 15.9mm diameter and 0.57mm wall thickness of cladding tubes and end caps have been used and optimum conditions of endcap welding have been selected. In this experiment, the qualification test was performed by tensile tests, helium leak inspections, and metallography examinations to qualify the endcap welding procedure. The soundness of the welds quality of a dual cooled fuel rods has been confirmed by mechanical tests and microstructural examinations.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.20 no.2
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• pp.137-142
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• 1984

An experimental study has been performed on the heat transfer characteristics of condensation by the injecting steam flow in the tube. The comparison between results of experimental data and available data concerning equivalent Reynolds number has studied. As the result, the followings were obtained. 1. The shear stress of the radial direction in the tube when the injecting steam flow was condensed can be written as root($\tau$sub(0)/$\tau$sub(0v))=1+1.46X sub(tt) super(0.20). 2. The effect of the heat transfer in the injecting steam flow was less than the value of equivalent Reynolds number. The reason are the nonuniform fluid film of the axial and radial direction in the tube. 3. The value of N sub(u) by the heat transfer of condensation can be written as N sub(u)=1.08$\times$[{$\rho$ sub(l) d/$\mu$ sub(l)}/{$\delta$+(2.5/P sub(rl)) ln(y sub(i)/$\delta$)}]$\times${$\tau$ sub(0)/ $\rho$ sub(l)} super(1/2).

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.189-192
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• 2002

In this study, The experimental open-tube-type and close-tube-type thermoacoustic refrigerator were constructed. The resonant characteristics of a thermoacoustic refrigerator were investigated. In order to determine the optimum resonant tube length and frequency, We changed the length of resonant tube from 400mm to 850mm and the frequency from 100Hz to 1000Hz. In case of first harmonic, the temperature difference of open-tube-type (1/4 wave) refrigerator was $41^{\circ}C$(resonator length :500mm). The temperature difference of close-tube-type (1/2 wave) refrigerator was $43^{\circ}C$(resonator length :850mm). In this experiments, the experimental 1/2 wave refrigerator is slightly cooler than the experimental l/4 wave refrigerator.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.7
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• pp.481-487
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• 2017

The interaction between a shock wave and a boundary layer causes boundary layer separation, shock train, and in some cases, strong unsteadiness in the flow field. Such a situation is also observed in a shock tube, where the reflected shock wave interacts with the unsteady boundary layer. However, only a few studies have been conducted to investigate the shock train phenomenon in a shock tube. In the present study, numerical studies were conducted using the two-dimensional axisymmetric domain of a shock tube, and compressible Navier-Stokes equations were solved to clarify the flow characteristics of shock train phenomenon inside a shock tube. A detailed wave diagram was developed based on the present computational results, which were validated with existing experimental data.