• 한국도로학회논문집
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• 제17권2호
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• pp.31-37
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• 2015

PURPOSES : To design a pre-heater for warm in-place recycling equipment, three different heating systems were evaluated to determine their thermal efficiency. METHODS: In this study, a $30cm{\times}30cm{\times}15cm$ wheel-tracking specimen was used to measure the inner temperature as a function of the heating system. The inner temperature of the specimen was measured with a data logger at the surface, and at depths of 1cm, 2cm, 3cm, 4cm, and 5cm. To evaluate the thermal efficiency, the researchers used three different types of equipment, namely, IR, a heating wire, and a gas burner. RESULTS: The IR heating system exhibits a higher level of performance than the others to achieve the target temperature at a depth of 5cm in the specimen. The gas burner system was capable of heating the surface to a temperature of up to $600^{\circ}C$. The other types, however, cannot heat the surface up to 600. The thermal efficiencies were measured based on the laboratory conditions. CONCLUSIONS: To find the most effective system for application to the development of a pre-heater for warm in-place recycling, various systems (IR, heating wire, gas burner) were examined in the laboratory. As a result, it was found that the hot plate of a gas burner system provides the highest temperature at the surface of the asphalt but, of all the systems, the IR system provides the best internal temperature increase rate. Furthermore, a gas burner can age the asphalt binder of the surface layer as a result of the high temperature. However, the gas burner cannot attain the target temperature at 5cm. The IR system, on the other hand, is effective at increasing the internal temperature of asphalt.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.935-936
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• 2012

• Journal of Advanced Marine Engineering and Technology
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• 제22권2호
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• pp.190-199
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• 1998

a new measuring method is suggested to determine the time constant of a thermocouple wire to be applied for the measurement of the true fluid temperatures in varying flow states. Based on the techniques of internal heating which are commonly used to measure mean time constants we extend the existing method to measure instantaneous time constants continuously. A method of measurement and analysis is presented and verified experimentally.

• 대한치과기공학회지
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• 제32권2호
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• pp.65-74
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• 2010

Purpose : To understand the impact on the strength or restoration force by the change of heating temperature when soldering 18-8 stainless steel round wire which is the chrome-nickel class for dental orthodontic device production. Methods : The following conclusions were made upon the results from tensile strength test, 3 point bending test, and $90^{\circ}$ bending fatigue test with 24 samples that had been applied with condition 1 (before heat treatment - natural) and condition 2 (after heat treatment - mooring 30 seconds after heating up to $500^{\circ}C$, $700^{\circ}C$, and $900^{\circ}C$) to ${\phi}0.4mm$, ${\phi}0.7{\beta}mm$, 18-8 stainless steel round wire (spring hard) by Jinsung Company. Results : When it was heat-treated at $900^{\circ}C$, both ${\phi}0.4mm$ and ${\phi}0.7mm$ showed very low tensile strengths compared to the heat treated cases at $500^{\circ}C$ and $700^{\circ}C$ Yield strengths of both ${\phi}0.4mm$ and ${\phi}0.7mm$ showed very low compared to the heat treated cases at natural, $500^{\circ}C$, and $700^{\circ}C$, as well. Upon the results of 3 point bending test, the heat treated case at $900^{\circ}C$ showed very low in both ${\phi}0.4mm$ and ${\phi}0.7mm$, compared to the heat treated cases at natural, $500^{\circ}C$, and $700^{\circ}C$. Tensile strength of both ${\phi}0.4mm$ and ${\phi}0.7mm$ as well, showed very low compared to the heat treated cases at natural, $500^{\circ}C$, and $700^{\circ}C$. Upon the results of $90^{\circ}$ bending fatigue test, the heat treated case at $900^{\circ}C$ showed the highest wave node resistance in both ${\phi}0.4mm$ and ${\phi}0.7mm$. Conclusion : This study concluded that heating temperature change during wire soldering impacts on the characteristics of orthodntic wire.

• 한국환경과학회지
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• 제24권2호
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• pp.237-244
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• 2015

This objectives of research are to figure out combustion characteristics with increasing temperature with petrochemical sludge by adding wasted organic matters which are waste electric wire, anthracite coal and sawdust, and to exam heating value and ignition temperature for using refused derived fuels(RDFs). After analyzing TGA/DTG, petrochemical sludge shows a rapid weight reduction by vaporing of inner moisture after $170^{\circ}C$. Gross weight reduction rate, ignition temperature and combustion rates represent 68.6%, $221.9^{\circ}C$ and 54.1%, respectively. In order to assess the validity of the RDFs, the petrochemical sludge by adding wasted organic matters which are waste electric wire, anthracite coal and waste sawdust. The materials are mixed with 7:3(petrochemical sludge : organic matters)(wt%), and it analyzes after below 10% of moisture content. The ignition temperatures and combustion rates of the waste electric wire, anthracite coal and waste sawdust are $410.6^{\circ}C$, $596.1^{\circ}C$ and $284.1^{\circ}C$, and 85.6%, 30.7% and 88.8% respectively. In heating values, petrochemical sludge is 3,600 kcal/kg. And the heating values of mixed sludge (adding 30% of the waste electric wire, anthracite coal and waste sawdust) each increase up to 4,600 kcal/kg, 4,100 kcal/kg and 4,300 kcal/kg. It improves the ignition temperatures and combustion rates by mixing petrochemical sludge and organic matters. It is considered that the production of RDFs is sufficiently possible by using of petrochemical sludge by mixing wasted organic matters.

• 한국정보통신학회논문지
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• 제23권10호
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• pp.1188-1194
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• 2019

유체의 흐름을 측정하는 여러 방법 중 열선 풍속 센서는 유체의 열전달에 의해 속도나 온도를 측정하는 장치로 비정상 속도 및 난류 속도 성분을 측정하는데 유용하다. 하지만 열선 풍속 센서는 외부의 환경 요인에 민감하며, 주변 온도, 습도, 신호 잡음 등에 의해 정확도가 떨어지는 단점이 있다. 이런 단점을 보완하는 방법으로 온도 보상 회로를 추가하는 기술이 나오고 있지만 가격 경쟁력을 갖출 수 없는 상황이다. 이를 해결하기 위해 본 논문에서는 온도 보상이 필요 없는 풍속 감지 센서에 대해 연구를 진행하였다. 열선식 풍속 센서는 외부 환경 요인 중에서도 주변 온도에 매우 취약하다. 주변 온도로는 전자 회로에 의한 발열의 영향이 가장 크게 미치고 있으며, 이를 개선하는 방법으로 발열체에 보조 발열체를 추가로 장착하여 보조발열체와 발열체의 일정한 온도차를 제어하는 것이다. 이와 같이 기존 기술에 비해 복잡하지 않은 방법으로 동등한 성능을 확보할 수 있다는 것을 확인할 수 있었다.

• 한국재료학회지
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• 제12권2호
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• pp.103-111
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• 2002

The thermally insulated underground pipelines have been used for district heating system. The sensor wire embedded in the insulation was used for monitoring the insulating resistance between the sensor wire and the pipe. The resistance measurement system detects corrosion of steel pipe under insulation. The corrosion and stress corrosion cracking(SCC) characteristics of sensor wire in synthetic ground water were investigated using the electrochemical methods and constant load SCC tests. The polarization tests were used to study the electrochemical behavior of sensor wire. The sensor wire was passivated at temperatures ranging from 25 to $95^{\circ}C$. However, the applied sensing current larger than passive current resulted in breakdown of passive film. The constant load SCC tests were performed to investigate the effects of applied current and load on the fracture behavior. Stress-corrosion cracks initiated at pits that were produced by sensing current. The growth of the pit involves a tunnelling mechanism, which leads to ductile fracture.

• 한국재료학회지
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• 제31권8호
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• pp.471-479
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• 2021

The electrochemical reaction between lead borate glass frit doped with Sn metal filler and Ni-Cr wire of a J-type resistor during a term of Joule heating is investigated. The fusing behavior in which the Ni-Cr wire is melted is not observed for the control group but measured for the Sn-doped specimen under 30 V and 500 mA. The Sn-doped lead borate glass frit shows a fusing property compared with other metal-doped specimens. Meanwhile, the redox reaction significantly contributes to the fusing behavior due to the release of free electrons of the metal toward the glass. The electrons derived from the glass, which used Joule heat to reach the melting point of Ni-Cr wire, increase with increasing corrosion rate at interface of metal/glass. Finally, the confidence interval is 95 ± 1.95₉ %, and the adjusted regression coefficient, R in the optimal linear graph, is 0.93, reflecting 93% of the data and providing great potential for fusible resistor applications.

• Nuclear Engineering and Technology
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• 제56권4호
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• pp.1125-1134
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• 2024

This paper presents a validation study of the subchannel analysis code SLTHEN used for the core thermal-hydraulic design of the Prototype Gen-IV sodium-cooled fast reactor (PGSFR). To assess the performance of the ENERGY model of SLTHEN, four liquid metal heating experiments conducted by ORNL, WARD, and KIT with hexagonal assemblies of wire-wrapped rod bundles were analyzed. These experiments were performed with 19-and 61-pin bundles and varying power distributions of axial and radial peaking factors up to 1.4 and 3.0, respectively. The coolant subchannel temperatures measured at different axial locations were compared with the SLTHEN predictions with the Novendstern, Chiu-Rohsenow-Todreas (CRT), and Cheng-Todreas (CT) correlations for flow split and mixing in wire-wrapped pin bundles. The results showed that the SLTHEN predicts the measured subchannel temperatures reasonably well with root-mean-square errors of ~10 % and maximum errors of ~20 %. It was also observed that the CRT and CT correlations consistently outperform the Novendstern correlation.

• 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.