• 한국지반환경공학회 논문집
• /
• 제18권1호
• /
• pp.5-12
• /
• 2017

한랭지역에 건설된 터널 라이닝은 터널주변 지하수의 결빙 등으로 인한 균열, 누수 및 백태 등이 빈번하게 발생하게 된다. 이러한 터널의 동결피해는 동절기 외기온도에 의해 터널내부 라이닝 및 배면의 지반온도의 하강으로 발생하게 되므로 시공 시 단열재를 설치하여 동결로 인한 피해를 저감하거나 기 시공된 터널에서는 단열재를 설치하거나 발열체 등을 설치하여 동결로 인한 피해를 저감할 수 있다. 본 연구에서는 대기온도의 변화에 의한 라이닝 배면의 지반온도 변화와 발열체가 설치되었을 경우 라이닝 및 배면 지반의 온도변화를 분석함으로써 동결피해 저감을 위한 대응방안 시 나타나는 효과를 분석하였다.

• 한국지반환경공학회 논문집
• /
• 제20권4호
• /
• pp.17-21
• /
• 2019

국내 한랭지역의 경우 고속도로터널 및 일반도로터널에서 발생하는 동결피해 사례는 조사 및 보고되고 있지만, 이에 대한 방안대책은 미흡한 상황이다. 한랭지역의 경우 영상권을 유지하는 다른 지역들과는 달리 평균온도가 영하로 떨어지는 지역이며, 동일지역 터널 내에서도 기온이 낮은 입출구에서 손상이 좀 더 발생하는 것으로 조사 되었다. 터널 라이닝의 온도저하를 방지하기 위하여 동절기에 라이닝의 온도를 강제로 상승시킬 수 있는 발열체를 제작하였다. 발열체는 실규모 터널의 라이닝에 부착하여 발열체의 열에 의한 터널 라이닝 주변의 온도변화를 측정하였다. 연구결과 발열체의 발열에 의해 라이닝의 온도상승 정도를 확인하였으며, 일정시간이 경과하면 라이닝의 온도상승이 수렴하는 것으로 나타났다. 이러한 결과를 활용하여 동절기 터널라이닝 및 배면의 동결피해를 줄일 수 있음을 확인하였다.

• 자원리싸이클링
• /
• 제23권2호
• /
• pp.46-52
• /
• 2014

본 논문은 마이크로파와 고온발열체에 의한 유류오염토양의 정화효율에 관한 연구를 정리한 것이다. 수분의 함량은 처리량에 따라 측정이 되었는데 상대적으로 짧은 시간에 300 g에 도달했다. TPH(Total Petroleum Hydrocarbons)처리 속도는 SiC 발열체를 단독으로 사용했을 때와 비교하였을 때, SiC와 활성탄을 4 kW/kg에서 동시에 사용했을 때 70.1%의 제거율로 가장 높은 값을 보여주었다. 특히, 3 kW/kg때를 제외하고는 전력이 증가할수록 처리속도도 증가하였다. SiC와 활성탄으로 제작된 발열체를 사용할 경우, 내부 온도가 $300^{\circ}C$를 초과하였으며, 4 kW로 2분동안 유지되었을 때 온도가 다시 하락하였으나, 8분이후에는 다시 온도가 상승하였다. 이러한 결과를 기초로 하여, 샘플을 처리하기 위한 에너지량은 마이크로파의 전력에 따라 계산이 되었으며, TPH처리 상수는 유류오염토양의 처리 특성에 관한 다양한 실험에 의해 측정이 되었다.

• 한국산학기술학회논문지
• /
• 제15권2호
• /
• pp.666-671
• /
• 2014

최근 디젤 차량과 같은 내연기관의 고효율화에 따라, 보조난방 열원으로서 PTC 히터의 사용이 증가하는 추세이다. 디젤 차량의 시동 초기에는 냉각수의 온도가 난방으로 직접 사용하기에 충분히 높지 않으므로, 동절기 난방을 위해 보조난방 열원은 필수적이다. 본 연구에서는 스크린 인쇄 전극공정을 바탕으로 한 PTC 소자를 제작하였고, 이를 활용한 PTC 소자 모듈 및 히터를 설계 및 제작하였다. PTC 소자 모듈의 방열핀 접촉형상 및 전열소자의 크기 변경에 따른 난방성능 변화를 열유동 해석을 통해 분석하였고, 난방성능 실험을 수행하여 PTC 히터의 난방성능 및 효율 특성을 살펴보았다. PTC 히터 시작품의 경우, 기존 PTC 히터와 동등한 수준 이상의 난방성능 및 효율을 나타내었으며, 향후 이를 바탕으로 PTC 소자와 히터에 대한 공정개선 및 성능증대 연구를 수행할 계획이다.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2004년도 추계학술대회논문집
• /
• pp.230-233
• /
• 2004

The purpose of this study is to establish the optimal induction heating conditions of various preform types used for TR forging. The finite element model coupled electro-magnetic and transient heat transfer was employed to evaluate the distribution of temperature at the billet. Power control method was applied to control temperature of preform in induction heating because TR forging is not a continuous process. Power schedule that consists of heating and holding stage was suggested. In heating stage, power is inversely proportional to diameter of preform but the time of heating stage is directly proportional to the diameter of preform. But, in holding stage, the required power for thermal equilibrium per unit volume of the billet decreases with an increase in a diameter of billet due to the increase of efficiency.

• 대한간호학회지
• /
• 제41권1호
• /
• pp.142-149
• /
• 2011

Purpose: The purpose of this study was designed to identify the effects of heat therapy on dysmenorrhea, heat being provided using a far infrared rays heating element. Methods: The research design for the study was a non-equivalent control group quasi- experimental design. Participants were 22 students for the experimental group, and 26 students for the control group. Data were analyzed using SAS WIN 9.1 program. Results: The experimental group had significantly lower mean scores for menstrual pain, dysmenorrhea, and blood pressure than those in the control group. However, no significant differences were found between two groups for pulse, respiration, and temperature. Conclusion: These findings show that thermotherapy was effective for reduction of menstrual pain, dysmenorrhea, and B/P. Therefore, this therapy could be used as a nursing intervention for students with dysmenorrhea.

• 한국주거학회논문집
• /
• 제21권6호
• /
• pp.1-9
• /
• 2010

The purpose of this study is to analyze the acceptance of the On-dol, Korean underfloor heating system, in the official residences built by the japanese colonist in 1905~1945. The On-dol is the main element that formed Korean housing culture throughout our her history. Since the climate of Korea is colder than that of Japan, the Japanese-style house built in Korea needed to take measures for the harsher winter. Therefore the official residences built during the japanese colonial period, built after the Japanese-style house, accepted the On-dol as additional heating system for their houses. Over forty years the official residences were constructed in large quantities, and many of the official residences also installed the On-dol. Some important changes were discovered about the acceptance of the On-dol. To define this concretely, this study was performed empirically through the comparison and analysis of governmental architectural drawings. There is great significance to consider that an architectural element of Korea influenced the Japanese-style houses. In conclusion, differences between the official residences with the On-dol and those without, during the latter stage of the japanese colonial period have founded. These results demonstrate that this element of traditional korean architecture affected the development of foreign houses built in Korea.

• 전기학회논문지
• /
• 제63권8호
• /
• pp.1098-1103
• /
• 2014

This study deals with the development of an electrofusion welding machine that is capable of joining plastic pipes using a recently developed electrofusion fitting. This fitting has built-in conductive plastics that are used to weld the joint together as a heating element. In order to explain the mechanism of the new machine, 1) the resistance characteristics of the heating element were explained, 2) the method of electric welding that uses the electrofusion fitting was described, and 3) the method of power supply based on controlling the firing angle was explained. A control system for an intelligent electrofusion welding machine was proposed. This system has the ability to recognize the diameter of an electrofusion fitting using a lookup-table based on the difference of resistance curves according to fitting types, and it is able to weld the fittings regardless of the ambient temperature. A new algorithm was developed to control the power of electric welding through the recognition of feature points from the resistance curve of the heating element. In order to evaluate the performance of the developed welding machine, tests involving the welding of 16 mm- and 20 mm-type fittings were carried out. Examining the welding results, we concluded that the proposed welding machine will offer high productivity and reliability in the field of electrofusion welding.

• 대한디지털의료영상학회논문지
• /
• 제12권2호
• /
• pp.145-150
• /
• 2010

Thick films of carbon fiber were prepared by a heating element of plan shape made in Darin co., We have investigated surface morphology of the specimen depending on heat-treatment temperatures. Scanning electron microscope(SEM) image of carbon fiber thick films of the specimen heat treated shows a grain growth at $1200^{\circ}C$ and becomes a poly-crystallization at $1350^{\circ}C$. The variation of resistivity at the thermally annealed specimen above $600^{\circ}C$ depends on type of the substrates. It may be due to a variation of film thickness and a difference of interfacial phenomena. A heating element of features was affected significantly by skin blood and quantity of heat of the body physiological function. After radiation of farinfrared for plate heating element, the function of biometric physiological is considered of skin blood flow and calorie which greatly affects on individuals. Electromagnetic wave was not influence on the body.

• 한국재료학회지
• /
• 제25권5호
• /
• pp.258-263
• /
• 2015

To fabricate porous SiC-Si composites for heating element applications, both SiC powders and Si powders were mixed and sintered together. The properties of the sintered SiC-Si body were investigated as a function of SiC particle size and/or Si particle contents from 10 wt% to 40 wt%, respectively. Porous SiC-Si composites were fabricated by Si bonded reaction at a sintering temperature of $1650^{\circ}C$ for 80 min. The microstructure and phase analysis of SiC-Si composites that depend on Si particle contents were characterized using scanning electron microscope and X-ray diffraction. The electrical resistivity of SiC-Si composites was also evaluated using a 4-point probe resistivity method. The electrical resistivity of the sintered SiC-Si body sharply decreased as the amount of Si addition increased. We found that the electrical resistivity of porous SiC-Si composites is closely related to the amount of Si added and at least 20 wt% Si are needed in order to apply the SiCSi composites to the heating element.