• 한국화재소방학회논문지
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• 제24권4호
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• pp.104-108
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• 2010

본 논문은 카본열선을 사용하는 전기장판에서 발생한 전기화재에 관하여 기술하였다. 카본열선을 사용하는 전기장판은 카본 재질의 특성상 전기용접이나 납땜 등의 방법으로 접속이 불가능하며, 열선 끝단을 카본 재질의 연결부를 만들어 접속해야 한다. 이러한 과정에서 열선 사이의 불완전 접속이 발생되며, 불완전 접속부에는 접촉저항의 증가로 국부적인 발열이 발생되고, 최종적으로 화재사고로 진전된다. 본 논문에서는 카본 열선 접속부에서 불완전 접속이 형성되는 경우, 접속부에서 전기적 발열에 의해 발생되는 열선의 손상 형태를 분석하여 화재원인을 규명하였다. 이러한 분석 결과는 카본 열선을 사용하는 전기장판의 화재원인 조사의 기초 자료로 활용 가능할 것으로 기대한다.

• 한국안전학회지
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• 제27권2호
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• pp.7-12
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• 2012

This paper describes electrical fire on electric pad caused by defect of hot wires. We analyzed two type electric pad using by carbon type hot wire and magnetic shielded type hot wire. First, a carbon type hot wires electric pad is virtually impossible to connect hot wire as a method of electrical welding or soldering. In order to connect between hot wires, that has to splice carbon type material connector. If junction of hot wires was occurrence of poor connection on electric pad, it increase contact resistance on this junction point. With increasing contact resistance, junction of hot wires on electric pad generates local heating and finally leads to electrical fire. An electric pad using by a magnetic shielded type hot wire happened local heating on signal wire for sensing temperature-rise caused by applying current for magnetic shielded. With increasing local heating of signal wire, insulated coating of hot wire was melted. Finally the magnetic shielded type hot wire electric pad lead to electrical fire with breakdown between signal wire and hot wire. In this paper, we analyzed shape of damage in hot wire caused by electrical local heating and investigated fire cause on electric pad due to defect of hot wires.

• 대한기계학회논문집B
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• 제28권5호
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• pp.510-517
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• 2004

A fine hot-wire is used both as a heating element and a temperature sensor in transient hot-wire method. The traditional sensor system is unnecessarily big so that it takes large fluid volume to measure the thermal conductivity. To dramatically reduce this fluid volume, a new sensor fabrication and a data processing method are proposed in this article. Contrast to the conventional and most popular two wire sensor, the new sensor system is made up of divided multiple long and short wires. Through validation experiments, it is found that the measured thermal conductivities of the glycerin are exactly same each other between the conventional and proposed new method. Also some technical considerations in arranging the multiple wires are briefly discussed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.210-215
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• 2003

A fine hot-wire is used both as a heating element and a temperature sensor in transient hot-wire method. The traditional sensor system is unnecessarily big so that it takes large fluid volume to measure the thermal conductivity. To dramatically reduce this fluid volume, a new sensor fabrication and a data processing method are proposed in this article. Contrast to the conventional and most popular two wire sensor, the new sensor system is made up of divided multiple long and short wires. Through validation experiments, it is found that the measured thermal conductivities of the glycerin are exactly same each other between the conventional and proposed new method. Also some technical considerations in arranging the multiple wires are briefly discussed.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.75-77
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• 2013

In this study, the characteristics of temperature history was evaluated for three hot wires with different capacity installed in slab concrete which are relatively thin. Results can be summarized as follows. First, for the case of material using 5W hot wire, all decreased to below zero at or around 24 hours. Similarly, the material using 20W hot wire decreased to 2℃ below zero at or around 80 hours but satisfied the accumulative temperature of 45° D·D at 7 days of material age. On the other hand, the case of 30W hot wire, the biggest capacity, showed the high temperature history of 5℃ in average at all areas except the corners. Thus, the target accumulative temperature was secured at or around the 3 days of material age. Considering the above, the initial damage by freezing can be prevented only if 20W or higher hot wires are used for the slabs at -10℃ of extremely low temperature environment.

• 대한기계학회논문집B
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• 제24권1호
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• pp.85-92
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• 2000

Easy measurement method of orthogonal triple-sensor hot-wire anemometer is developed. Advantages of the new method is that it does not require either the exact orthogonality of the installed wires which cannot be kept during the probe manufacture and repair, nor the knowledge of the wire installation angles and the yaw and pitch coefficient of the wires. The new method introduced yaw and pitch calibration coefficients which are designed to increase monotonically with yaw and pitch angles. So the resulting calibration network is simple to recognize compared with that of the previously suggested calibration method. Verification experiments showed good accuracy and independency of the directional calibration on velocity.

• Nuclear Engineering and Technology
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• 제55권7호
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• pp.2534-2546
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• 2023

Gas-cooled space reactor, which adopts He-Xe gas mixture as working fluid, is a better choice for megawatt power generation. In this paper, thermal-hydraulic characteristics of He-Xe gas mixture in 2×2 rod bundle wrapped with helical wires is numerically investigated. The velocity, pressure and temperature distribution of the coolant are obtained and analyzed. The results show that the existence of helical wires forms the vortexes and changes the velocity and temperature distribution. Hot spots are found at the contact corners between helical wires and fuel rods. The highest temperature of the hot spots reach 1600K, while the mainstream temperature is less than 400K. The helical wire structure increases the friction pressure drop by 20%-50%. The effect extent varies with the pitch and the number of helical wires. The helical wire structure leads to the reduction of Nusselt number. Comparing thermal-hydraulic performance ratios (THPR) of different structures, the THPR values are all less than 1. It means that gas-cooled space reactor adopting helical wires could not strengthen the core heat removal performance. This work provides the thermal-hydraulic design basis for He-Xe gas cooled space nuclear reactor.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(II)
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• pp.981-986
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• 2002

ACSR of the catenary wires is corrosion degradation progressed by the effect of atmospheric pollution. ACSR which consists of galvanized steel stranded aluminum. The inside of Steel Reinforced is hot-dipped zinc coating steel wire and it takes charge of tension. If ACSR is exposed in atmosphere, the galvanic corrosion is occurred because it is contacted with aluminum. It is occurred the chemical reaction rapidly so that the local a defect is also occurred. If the catenary wires are exposed in atmosphere of pollution conditions, it may cause to reduce the mechanical strength by corrosion degradation and may cause to damage the wires by micro cracks. Accordingly, this study presents the effects of mechanical properties through the corrosion of ACSR.

• 정보통신설비학회논문지
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• 제8권2호
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• pp.84-89
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• 2009

This paper has purpose of designing the earthing system installed on the ground without laying under the ground. As a solution for green IT environment to solve the existing earthing system, the third generation earthing machine was designed by using discharge electrodes, catalyzer, and hot wires. As a result of comparison, it found that the third generation earthing system suggested in this research had more increased discharge currents by 31[A] and the speed 25 times faster than the second generation earthing system. The suggested earthing system is allowed to be installed on the ground and solve construction costs, time, area, and environment pollution, which are problems in the existing earthing system. In addition, as the earthing technique has recently developed, the earthing system is classified by generation based on capacity.

• Journal of Welding and Joining
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• 제33권6호
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• pp.36-41
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• 2015

In the automotive industry, TWB hot stamping process is broadly adapted to reduce weight of the car and improve fuel efficiency. However, the process faces a problem of weakened strength of the welded zone after hot stamping process, due to the fact that Al-Si elements of the coating layer penetrating the welded zone. In this study, filler wires with high percentages of carbon and manganese is adapted during laser welding process to secure the strength of the fusion zone. In addition, wire feeding speed and laser welding speed are optimized by sample test.