• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.3
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• pp.350-356
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• 2011

In this paper, we proposed the automatic cutting mechanism of the perforation pipes in an automobile muffler. This cutting mechanism makes continuous work possible, because it performs the batch work via the sequential operation of loading, feeding, cutting, and discharging. The proposed cutting mechanism consists of the frame unit, escape unit, turning unit, feeding unit, vision system, clamping unit, spindle/cutting unit and cooling unit. And, these mechanisms have been modularized through mechanical, dynamical and structural optimized design using the SMO (SimDesigner Motion) analysis module. Also, the virtual prototype was carried out using the 3-D CAD program. The cutting process cycle is performed in the order of loading, vision processing, feeding, clamping, cutting and discharging. And the cycle time for cutting one piece was designed to be completed in four seconds.

• Solar Energy
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• v.11 no.2
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• pp.34-40
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• 1991

Thermal stratification enhancement for the higher extraction efficiency of hot water storage tank was experimentally studied with transparent fiber glass cylindical tank($350{\ell}$, D=516mm, H=1680mm). Height to diameter ratio (H/D =1,2,3), flow rate(Q= 8,10,12LPM), inlet-outlet temperature differences(${\Delta}T=20,25,30^{\circ}C$), and geometry of inlet-outlet port were the parameters. In particular, three kind of distributors were used for geometry of inlet-outlet port. As a result, it was possible to get extraction efficiency of 95% by using the distributor having variable diameter but keeping a constant diameter of perforation. So it is recommendable to design the distributor so that the main pipe decrease in diameter toward the dead end.

• Proceedings of the KIEE Conference
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• summer
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• pp.1367-1369
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• 2004

When an underground pipeline runs parallel with subway DC electrification system, it suffers from stray current corrosion caused by the stray current from the rails negative returns. Perforation due to the stray current corrosion may bring about disastrous accidents such even in cathodically protected systems. Traditionally, bonding methods such as direct drainage, polarized drainage and forced drainage have been used in order to mitigate the damage on pipelines. In particular, the forced drainage method is widely adopted in Busan. In this paper, we report the real-time measurement data of the pipe-to-soil potential variation in the presence and absence of the IR compensation. The drainage current variation was also measured using the Stray Current Logger developed. By analyzing them, the problems of current countermeasures for stray current corrosion are discussed.

• Water for future
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• v.19 no.2
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• pp.131-138
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• 1986

Both hydraulic and dynamic characteristics of a single perforated wall are studied theoretically and experimentally. Theoretically, the effect of evanescent modes on wave force acting on a single perated wall is studied by use of the Horiguchi theory. The wave force on the perforated wall is presented to be insensitive to evanescent modes. According to experimental study, The larger perforation ratio(${\gamma}$) grows, the weaker the wave force on the wall becomes sensitively. And in the small value of l/D (ratio of wall thickness(l) to hole diameter(D)) where the holes on the wall are regarded as orifice, the wave force on the wall is insensitive to the variation of l/D. Energy loss coefficient f is estimated at 1.0 in this small value of l/D by use of Horiguchi theory. But in the large value of l/D where the holes are regarded as pipe, the wave force on the wall is relatively sensitive to the variation of l/D and f is estimated at 1.5 by use of Horiguchi theory.