• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.3
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• pp.123-129
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• 2000

To make high accuracy cutting of long materials and a piston for the engines it must be necessary to keep the thermal stability of spindle and tail stock in CNC lathe. If a object is clamped at the ends the thermal expansion and cutting process generate the deflection of cutting objects. Especially in the case of a piston ring piston ovality and piston profile the influences of deflection are very serious. In order to solve the problems most of piston cutting are worked under simply support. However the prob-lems exist yet. Therefore this paper proposes the new structure of tail stock which can compensates the deflection.

• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.8
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• pp.1095-1106
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• 2013

This study evaluated the wear comfort properties of water-vapor-permeable (WVP) garments using a movable sweating thermal manikin. Manikin tests were performed in a climatic chamber (temperature T=20, $35{\pm}0.5^{\circ}C$ and relative humidity $H=50{\pm}10%$) using seven sportswear outfits (a long sleeve shirts and a long pants) made with seven different WVP fabrics. Physiological responses of wear trials could be correlated with measurement parameters of the thermal manikin experiment; subsequently, a regression model that represented a final comfort sensation could be obtained. The regression model developed in this work is based on thermal manikin measurements; consequently, it provides an independent comfort sensation level in a relatively short time at a low cost while maintaining the reproducibility of results. It translates into more actual choices for sportswear manufacturers and sportswear consumers.

• Explosives and Blasting
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• v.17 no.4
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• pp.8-17
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• 1999

Unfortunately leaks occur in heat exchangers periodically, usually at the tube to tubeplate joint. The usual method of repair is to plug off the defective area and isolate the tubes of concern from the circuit. If the leaks continua the thermal capacity of the units is progressively reduced and for this reason the alternative of using an internal bridging sleeve has been examined. This paper discusses the overall development activities that has been found necessary to bring this repair procedure to a successful conclusion for use on the nuclear steam generator. In this work we have investigated optimum explosives and explosive quality, explosive sleeving's thickness, the design of sheath stress relieving heat treatment pull-out load, hydraulic leakage, stress corrosion cracking properties. The results obtain are as follows : (1) The optimum explosives and explosive qualities are PETN and about 15~40 gr/ft of explosive sleeving in nuclear steam generator. (2) Explosive sleeving's thickness is 1.1~l.4mm, If groove of 0.35mm formed in sleeve outside existed, For the hydraulic leakage is go up, explosive sleeving of formed groove are applicate tube and turnplate. (3) If the stress relieving heat treatment are experiment in $750^\circ{C}$, $850^\circ{C}$, 15 minutes Pull-out strength of sleeving 1,500~2,300kg, hydraulic leakage is $250kg/cm^2$.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1516-1519
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• 2004

A tele-operated robot should be used to maintain and inspect nuclear power plants to reduce the radiation exposure to the human operators. During an overhaul of the nuclear power plants in Korea, a ROV(Remotely Operated Vehicle) may enter a cold-leg connected to the reactor to examine the state of the thermal sleeve and it's position in the safety injection nozzle. To measure the positions of the thermal sleeve or scratches from the video images captured during the examination, the camera parameters should be identified. However, the focal length of the CCD camera could be increased to a close up of the target and the aspect ratio and the center of the image could also be varied with capturing devices. So, it is desired to self-calibrated the intrinsic parameters of the camera and capturing device with the video images captured during the examination. In the video image of the safety injection nozzle, two or more circular grooves around the nozzle are shown as ellipse contours. In this paper, we propose a camera self-calibration method using a single image containing two circular grooves which are the greatest circles of the cylindrical nozzle whose radius and distance are known.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.12
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• pp.73-85
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• 1997

The rolling force and roll deformation behavior in the twin roll type strip continuous casting process has been computed to estimate the thermal charcteristics of a caster roll. To calculation of rolling force, the relationship between flow stress and strain for a roll material and casting alloy are assumed as a function of strain-rate and temperature because mechanical properties of a casting materials depends on tempera- ture. The three dimensional thermal dlastic-plastic analysis of a cooling roll has also been carried out to obtain a roll stress and plastic strain distributions with the commercial finite element analysis package of ANSYS. Temperature fields data of caster roll which are provided by authors were used to estimated of roll deformation. Roll life considering thermal cycle is calculated by using thermal elastic-plastic analysis results. Roll life is proposed as a terms of a roll revolution in the caster roll with and without fine failure model on the roll surface. To obtain of plastic strain distributions of caster roll, thermomechan- ical properties of roll sleeve with a copper alloy is obtained by uniaxial tensile test for variation of temperature.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.361-366
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• 2000

To make high precision cutting of long materials or a piston for the engines, it must be necessary to keep the stability of spindle and tail stock in CNC lathe. If a object is clamped at the ends, the thermal expansion and cutting generated in cutting process appear as the deflection of in cuttings objects. Especially, of a piston ring, piston ovality and piston profile, the influences are very serious. In order to solve the problems most of piston cutting are worked in simply support. However, the problems exist, yet.

• Corrosion Science and Technology
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• v.18 no.5
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• pp.190-195
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• 2019

SA508 low-alloy steel for a reactor vessel was exposed to primary water in a pressurized water reactor (PWR) plant because the cladding layer of type 309 stainless steel for the RPV was removed, due to an accident in which the detachment of the thermal sleeve occurred. The major advantage of the electrochemical deposition (ECD) Ni plating technique is that the reactor pressure vessel can be repaired without significant thermal effects, and Ni has solid corrosion resistance that can withstand boric acid. The corrosion rate assessment of the damaged part was performed, and its trend was analyzed. Essential variables of the Ni plating for repair of the damaged part were derived. These conditions are applicable variables for the repair plating device, and have been carefully adjusted using the repair plating device. The process for establishing ASME technical standards called Code Case N-840 is described. The process of developing Ni-plating devices, and the electroplating procedure specification (EPS) are described.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.9
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• pp.963-968
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• 2009

This paper deals with shrink fit analysis of rotor by 2D cross-section, 2D axis-symmetry, and 3D FEM model. And this paper presents 2nd order approximation function of thermal expansion displacement by design variables (shape dimension, heating temperature, sleeve length, interference etc.), table of orthogonal array and RSM(response surface methodology). The possibility of the rotor with shrink fit is evaluated by thermal expansion displacement. If thermal expansion displacement is larger than interference, shrink fit enable to make the rotor. 2D axis-symmetry model and 3D model are more reasonable than 2D cross-section model, because stress and strain is different along length of shaft.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.7
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• pp.1042-1049
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• 1997

LMFBR(Liquid Metal Fast Breeder Reactor) vessel is operated under the high temperatures of 500-550.deg. C. Thus, transient thermal loads were severe enough to cause inelastic deformation due to creep-fatigue and plasticity. For reduction of such inelastic deformations, Y-piece structure in the form of a thermal sleeve is used in LMFBR vessel under repeated start-up, service and shut-down conditions. Therefore, a systematic method for inelastic analysis is needed for design of the Y-piece structure subjected to such loading conditions. In the present investigation, finite element analysis of heat transfer and inelastic thermal stress were carried out for the Y-piece structure in LMFBR vessel under service conditions. For such analysis, ABAQUS program was employed based on the elasto-plastic and Chaboche viscoplastic constitutive equations. Based on numerical data obtained from the analysis, creep-fatigue damage estimation according to ASME Code Case N-47 was made and compared to each other. Finally, it was found out that the numerical predictio of damage level due to creep based on Chaboche unified viscoplastic constitutive equation was relatively better compared to elasto-plastic constitutive formulation.

• Journal of the Korean Society of Clothing and Textiles
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• v.14 no.1 s.33
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• pp.20-30
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• 1990

In order to investigate the mechanism of the formation of clothing microclimate with different blouse designs and materials, physiological and subjective sensational changes were measured. Experimental clothing were four types of blouse made of $100\%$ cotton, $100\%$ regular polyes­ter, and $100\%$ hygroscopic polyester. Four types of box style blouse were with stand collar and long sleeve, with stand collar and sleeveless, with long sleeve and collarless, and sleeveless and collarless. Five healthy female were chosen as subjects. Experiments were carried out in the environ­mental chamber controlled at $28{\pm}1^{\circ}C$ , $70{\pm}5\%$ RH. and still-air condition for SO min. The skin temperature (9 spots), oral temperature, humidity inside chest, and subjective sensations were measured. Obtained results are: I) Material which is capable of absorbing sweat effectively and transfering moisture rapidly made a comfortable feeling, because cloth­ing humidity is increasing slowly at this material. 2) During exercise period, covered arms have more influenced on thermal comfort than a covered neck.