• 한국안전학회지
• /
• 제27권3호
• /
• pp.57-62
• /
• 2012

The purpose of this paper is to find dangerous factors of a water purifier when water leaks due to inappropriate use and analyze the patterns of damaged parts in order to provide data for the examination of the cause of the problem. If the water purifier is inspected and managed by a non-specialist, when the FLC(Float Level Controller) at the top is inclined, water leakage may occur to the water purifier. The leaked water flows onto the cables and hoses and enters the thermostat terminal, heater, PCB, power supply connection connector, etc., becoming a dangerous factor that may cause a system failure, fire, etc. Due to the water that entered the input terminal, low noise and white smoke were generated at first. However, the flame gradually propagated due to the continuous inflow of moisture. It was found that when moisture reached the PCB, a carbonized conductive path was formed at the varistor terminal, input terminal, semiconductor device terminal, etc., and the flame became larger, which might result in a fire. From the metal microscope analysis of a damaged condenser terminal, it was found that the amorphous structure unique to copper cable disappeared, and voids, boundary surface and disorderly fine particles occurred. Also, in the case of the connector into which moisture penetrated, fusion and deformation occurred at the cable connection clips. The result of analysis of the power supply cable connector using a thermal image camera showed that most of the heat was generated from the cable connection clips and the temperature at the connection center was normal.

• Structural Engineering and Mechanics
• /
• 제80권5호
• /
• pp.503-522
• /
• 2021

This paper investigates experimentally and numerically the influence of drilling process on the mechanical and thermomechanical behaviors of woven glass fiber reinforced polymer (GFRP) composite plate. Through the experimental analysis, a CNC machine with cemented carbide drill (point angles 𝜙=118° and 6 mm diameter) was used to drill a woven GFRP laminated squared plate with a length of 36.6 mm and different thicknesses. A produced temperature during drilling "heat affected zone (HAZ)" was measured by two different procedures using thermal IR camera and thermocouples. A thrust force and cutting torque were measured by a Kistler 9272 dynamometer. The delamination factors were evaluated by the image processing technique. Finite element model (FEM) has been developed by using LS-Dyna to simulate the drilling processing and validate the thrust force and torque with those obtained by experimental technique. It is found that, the present finite element model has the capability to predict the force and torque efficiently at various drilling conditions. Numerical parametric analysis is presented to illustrate the influences of the speeding up, coefficient of friction, element type, and mass scaling effects on the calculated thrust force, torque and calculation's cost. It is found that, the cutting time can be adjusted by drilling parameters (feed, speed, and specimen thickness) to control the induced temperature and thus, the force, torque and delamination factor in drilling GFRP composites. The delamination of woven GFRP is accompanied with edge chipping, spalling, and uncut fibers.

• Journal of Acupuncture Research
• /
• 제21권1호
• /
• pp.226-239
• /
• 2004

Objective: Purpose of this study was to examine the effect of electroacupuncture(EA) at Xingjian(LR2) as 'Fire(火)' point of The Leg Absolute Um Liver Meridan(足厥陰肝經 : Chok-Kworum-Kan-Kyong) on the facial thermal change. Methods: Subjects of this study were 15 patients with upperpart(includes head and facial part) fever of human body and two examinations were carried out in each other day. We divided cases of two examinations into two groups. One is experimental group(N=15) that was carried out electroacupuncture stimulation at Xingjian(LR2), the other is control group(N=15) which was carried out electroacupuncture stimulation at optional point(in space between 1st and 2nd fingers) except acupuncture points of 12 meridians. We took the temperature of fixed areas on face by digital infrared thermal image(D.I.T.I.) before and after electroacupuncture stimulation. Those fixed areas on face that was taken temperature are Jingming(BL1), Sibai(ST2), Dicang(ST4), Indang, Shuigou(GV26), Chengjiang(CV24) areas. In cases of temperature of Jingming(BL1), Sibai(ST2), Dicang(ST4) areas, we applied each mean of left and right temperature to statical analysis. Results: In the group of electroacupuncture stimulation at Xingjian(LR2), temperature of every fixed areas on face fell: Jingming(BL1) area's ${\Delta}T=-0.7007{\pm}0.78642$, Sibai(ST2) area's ${\Delta}T=-0.6280{\pm}0.56439$, Dicang(ST4) area's ${\Delta}T=-0.5940{\pm}0.60179$, Indang area's ${\Delta}T=-0.7200{\pm}0.64515$, Shuigou(GV26) area's ${\Delta}T=-0.6160{\pm}0.80487$, Chengjiang(CV24) area's ${\Delta}T=-0.5627{\pm}0.72615$. In Xingjian(LR2) electroacupuncture group, each temperature of Jingming(BL1), Sibai(ST2), Indang areas showed a drop significantly in comparison with control group (p<0.05). But each temperature of Dicang(ST4), Shuigou(GV26), Chengjiang(CV24) areas did not showed a drop significantly in comparison with control group(p>0.05). Conclusions: The results mentioned above showed that electroacupuncture stimulation at Xingjian(LR2) significantly decreased the temperature on face of patients with upperpart fever of human body. In Xingjian(LR2) electroacupuncture group, especially temperature of upper part of face includes eye, cheekbone, forehead regions showed a drop significantly in comparison with control group.

• 열처리공학회지
• /
• 제25권1호
• /
• pp.6-13
• /
• 2012

HVOF thermal spray coating of 80%WC-CoFe powder is one of the most promising candidate for the replacement of the traditional hard chrome plating and hard ceramics coating because of the environmental problem of the very toxic $Cr^{6+}$ known as carcinogen by chrome plating and the brittleness of ceramics coatings. 80%WC-CoFe powder was coated by HVOF thermal spraying for the study of durability improvement of the high speed spindle such as air bearing spindle. The coating procedure was designed by the Taguchi program, including 4 parameters of hydrogen and oxygen flow rates, powder feed rate and spray distance. The surface properties of the 80%WC-CoFe powder coating were investigated roughness, hardness and porosity. The optimal condition for thermal spray has been ensured by the relationship between the spary parameters and the hardness of the coatings. The optimal coating process obtained by Taguchi program is the process of oxygen flow rate 34 FRM, hydrogen flow rate 57 FRM, powder feed rate 35 g/min and spray distance 8 inch. The coating cross-sectional structure was observed scanning electron microscope before chemical etching. Estimation of coating porosity was performed using metallugical image analysis. The Friction and wear behaviors of HVOF WC-CoFe coating prepared by OCP are investigated by reciprocating sliding wear test at $25^{\circ}C$ and $450^{\circ}C$. Friction coefficients (FC) of coating decreases as sliding surface temperature increases from $25^{\circ}C$ to $450^{\circ}C$.

• 한국화재소방학회논문지
• /
• 제27권2호
• /
• pp.40-45
• /
• 2013

전기화재는 다양한 원인에 의해 발생하고 있으며 최근에는 복합적인 원인에 의해 발생하기 때문에 전기적, 열적, 기계적, 환경적 영향에 의한 제품의 열화특성과 발열 메커니즘 등 체계적인 연구와 분석을 통한 과학적이고 합리적인 안전설계애안 제시를 위한 연구가 절실히 요구되고 있는 실정이다. 재해로 인한 인적 물적 손실은 국가와 기업의 대외 신뢰도 하락을 가져오고 있으며 제품 안전에 대한 수요는 무한 경쟁에 따른 규제완화의 이유로 증가하고 있다. 기업의 이미지를 증진시키고 국제적 경쟁력을 강화시키기 위해 제품에 대한 안전 설계는 반드시 필요하다. 본 논문에서는 사용량이 점차 증가하고 있는 에어컨에서 전기화재가 발생한 사례와 원인 및 재현실험을 통해 안전설계에 대한 제시를 위해 수행 하였으며 화재 예방대책 등의 기초 자료로 할용 가능할 것으로 기대한다.

• 대한한방부인과학회지
• /
• 제26권4호
• /
• pp.94-106
• /
• 2013

Objectives: The purpose of this study is to find the effect of Far Infrared Radiation (FIR) about improvement of chief complaints and health state. Methods: For this study we evaluated thermographic images, heart rate variability (HRV), visual analogue scale (VAS) score of 34 patients with various diseases. Tests were done two times, before and after treatments and we compared the test results. We used the temperature difference between CV12 and CV4, both sides of PC8, LR3 for recognizing improvement of blood circulation. We analyzed the change of complexity, stability of autonomic nervous system (ANS) by HRV test. The patients were asked to fill out questionnaire about the severity of symptoms by VAS score. Analyses were undertaken using SPSS ver.12.0.1 and p-value of < 0.05 was considered significant. Results: Statistical analysis shows that Far Infrared Radiation (FIR) had significant efficiency in increasing surface temperature and reducing VAS pain scores. In heart rate variability (HRV) test, LF/HF ratio showed tends to improve. Conclusions: The application of an FIR to whole body appears to alleviate various complaints of patients.

• 대한기계학회논문집B
• /
• 제26권9호
• /
• pp.1276-1283
• /
• 2002

Recently, HSDI (High Speed Direct Injection) diesel engine has been spotlighted as a next generation engine because it has a good potential for high thermal efficiency and fuel economy. This study was carried out to investigate the in-cylinder flow characteristics generated in a 4-valve small diesel cylinder head with a tangential and helical intake port. The flow characteristics such as coefficient of flow rate(Cf), swirl ratio (Rs), and mass flow rate (ms) were measured in the steady flow test rig using the impulse swirl meter and the analysis of in-cylinder flow field was conducted by experiment using the PIV and calculation using the commercial CFD code. As the results from steady flow test indicate, the mass flow rate of the cylinder head with a short distance between the two intake ports is increased over 13% than that of the other head. However, the non-dimensional swirl ratio is decreased approximately 15%. From in-cylinder flow characteristics obtained by PIV and CFD calculation, we found that the swirl center was eccentric from the cylinder center and the velocity distribution became uniform near the TDC. In addition, the results of the calculation are good agreement with the experimental results.

• 지질공학
• /
• 제26권1호
• /
• pp.23-32
• /
• 2016

ASTER 위성영상을 이용하여 팽창성 점토광물인 일라이트 인자 추출 및 SVM 통계분석을 통해 산사태 취약성을 평가하였다. 연구지역의 산사태 발생지역은 항공사진 판독 및 현장 조사를 통해 분석하였다. GIS 기반 공간데이터베이스로는 지형도, 토양도, 임상도, ASTER 위성사진을 이용하였다. 수치지형도에서는 경사 및 경사방향, 곡률도, 계곡과의 거리, 도로와의 거리, 토양도에서는 유효토심, 토질, 토양지형, 토양 배수정도 및 토양 모재, 임상도에서는 경급, 영급 및 밀도를 위성사진에서는 일라이트 인자를 추출하였다. 산사태 발생요인 데이터베이스와 SVM 통계분석 및 가중치 계산을 통해 각 요소간의 상관관계 취약성도를 구하였다. AUC 검증 결과 일라이트 인자 적용결과는 76.46%의 예측 정확도를 보였으며 일라이트 인자 미적용 모델은 74.09%의 예측 정확도를 나타내었다. 이는 일라이트 인자가 산사태 취약성도 작성에 있어 중요한 자료로 사용될 수 있음을 나타낸다.

• 대한전자공학회논문지
• /
• 제26권7호
• /
• pp.83-89
• /
• 1989

강유전성 $PbTiO_3$ 박막을 rf스터링으로 기판온도 $100{\sim}150^{\circ}C$에서 형성시켰다. 이 박막의 구조는 X선 회절결과 비정질 형태로 파이로클로어 구조를 갖고 있었다. 이 박막을 열에 의해 어닐링한 경우는 $550^{\circ}C$에서, 레이저의 주사로 어닐링한 경우는 레이저 출력이 50watts일때 가장 우수한 결정 구조를 구할 수 있었다. 집합에서의 계면 특성을 구하기 위하여 MFS(metal-ferroelectric-semiconductor)및 MFOS(metal-ferroelectric-oxide-semiconductor) 구조를 형성하여 C-V특성을 조사하였다. 이때 MFS보다 MFOS의 경우가 Si표면에 sputter에 의한 결함이 작음을 알 수 있었다.

• Journal of Acupuncture Research
• /
• 제24권3호
• /
• pp.215-229
• /
• 2007

Objectives : Placebo phenomena have been considered as a confounding factor of clinical trial. Expectancy and belief of acupuncture have not been evaluated quantitatively. The present study was performed to analyze the emotional and cognitive factor .of acupuncture and investigate whether the expectancy of acupuncture treatment is associated with the cognition of acupuncture. Methods : The expectancy and the perception of bodily sensation (PBS) of 22 participants were assessed using self-reported questionnaire. The subjects used the self assessment manikin (SAM) to rate each of the standard affective image of the international affective picture system (lAPS) and other acupuncture-related image. Based on the degree of expectancy, the high expectant (HE) and the low expectant (LE) group were classified. The thermal and pressure pain threshold was objectively evaluated using radiant-heat device and algometer. The degree of expected pain of acupuncture and the actual pain of painful stimulation was subjectively evaluated using facial pain scales (FPS). Results : Using SAlVI analysis, we identified the negative correlation between hedonic valence and arousal dimension on acupuncture-related visual cue. The degree of the PBS and general pain threshold did not show any significant difference between the HE and the LE group. The HE group rated the acupuncture images as more pleasant, more arousing, than the LE group. In addition, we also found that the higher expectancy marked the lower FPS of the expected pain of acupuncture, but not of the actual pain of painful stimulation. Conclusions : Our preliminary study identified the psychological dimensions of acupuncture-related visual cue. These findings indicate that the expectancy of acupuncture could affect the cognition of acupuncture.