• 한국안전학회지
• /
• 제27권5호
• /
• pp.179-184
• /
• 2012

This study was performed to find out the measurement criteria of slip resistance from analysis of human gait and slips. Many kinds of slip resistance testers were developed based on mechanical friction testers. But, there are, as yet, no unambiguous slip resistance measurement methodologies and generally accepted safety criteria or safety thresholds for estimating slipping hazard exposures. Also, there are variety of measuring conditions between those testers. The measurement criteria should be tested within the range of human slipping conditions observed in biomechanical studies. It's results should clearly consider whether the devices reflect the human slipping conditions. In this study a dragsled type friction tester, which was constructed in accordance with ISO 15133 basically, was used. Test conditions were set in order to determine the range of measurement criteria. It is shown that drag velocity should be more than 1 m/s, acceleration be more than 10 $m/s^2$, contact time be less than 0.1sec, and contact pressure be within 350~400 kPa.

• 한국기계가공학회지
• /
• 제6권2호
• /
• pp.22-27
• /
• 2007

In this study, the two methods of stiffness measurement(Spring constant) of cantilever were proposed for quantitative measurement in Atomic Force Microscopy(AFM). As the 1st method for the measurement of stiffness, the probe method, which is used in the measurement of the semiconductor mechanical and electrical properties, was applied to the measurement of the cantilever. Experiments by the probe method were performed finding the resistance value of cantilever. As the results, the resistance was measured differently along with the dimension and the thickness of cantilever that determined the stiffness(spring constant) of the lever. As the 2nd method, the vibration characteristics(Dunkerley expression) is used to obtain the stiffness of the complex structure which is combined by AFM cantilever and the standard cantilever. We measured the resonant frequency from the complex structure using the micro stages and stereo microscope. As the results, we confirmed that the vibration characteristics(Dunkerley expression) is effected the micro complex structure of AFM cantilever.

• 센서학회지
• /
• 제16권4호
• /
• pp.263-269
• /
• 2007

Although variable resistance displacement transducer is widely applied for its technical simplicity, electrical point contact limits measurement resolution (precision). The present study introduced roller shaped structure for electrical line contact. Proto-type transducer was developed and measurement characteristics were compared with a commercialized product. When the displacement was varied with steps of 5 mm, 1 mm, and down to 0.1 mm, the correlation coefficient between resistance and displacement decreased lower than 0.9 in the commercialized product while the proto-type transducer maintained values higher than 0.99. Therefore, the measurement resolution was enhanced by approximately 10 times. Since manufacturing also seemed easier, the present results would enable more accurate and less expensive manufacturing of variable resistance displacement transducer.

• 한국안전학회지
• /
• 제14권1호
• /
• pp.66-72
• /
• 1999

Local heating transportation pipe has sensor and return lines to detect water-leakage. There are impulse and resistance comparison measurement types for a water-leakage detection. The impulse type shows large detection error within a measurement range. Since the resistance comparison type can find a comparative accurate single water-leakage point in the measurement range of heating pipe, it has been used to detect water-leakages these days. However if the multi water-leakages are happened in the measurement range of transportation pipe. the resistance comparison type shows a detection error point by the parallel resistance between a detection sensor line and ground. But the detection error will be minimized by the divided transportation pipe loops. In this research, it suggests the design of remote controlled detection system which can divide a large pipe loop and a possible single water-leakage measurement process in each divided loops.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
• /
• pp.426-429
• /
• 1999

In this paper, we have provided the measurement technique of the grounding mesh resistance by field measurements. The standard of measurement is specified in the IEEE Std 81.2-1991 and JEAC 5001-1988, which is the the fall-of-potential method by test-current injection, but this method is difficult to apply at field, where is small around a electric power substation of domestic. For the convenient measurement method, space of assistant probe and quantity of test-current injection are changed step for step. As the result, ' the proposed measurement technique of grounding mesh resistance is that the space of current and potential probes must be fixed at 150rn from a grounding mesh, the test-current injection has to keep 5A or more.

• 한국도로학회논문집
• /
• 제14권4호
• /
• pp.1-8
• /
• 2012

PURPOSES : Skid resistance on pavements plays an important role in reducing the risk of vehicle skidding on wet surface particularly. Almost 9.3 percent of traffic accidents were occurred under rainy condition and these are over-represented in terms of the severity of the crashes. Recently, unusual weather conditions referred widely as the intensified rainfalls justify the need of a systematic management of skid resistance. In this context, the study carried out the observational study on the skid resistance characteristics of different types of pavement with the time passage. METHODS : This study measured the skid resistance with Pavement Friction Tester at three times within five years. The skid resistance measurement has followed the method suggested by ASTM. RESULTS : As the main results under the scope of this study, skid resistance of asphalt concrete has not nearly reduced with time. On the contrary, skid resistance of cement concrete has been rapidly reduced with time though the highest resistance was gained at the early observation. Porous asphalt concrete shows a steady decrease of skid resistance with time, anyway, the reduction rate according to the increase of measurement speeds is relatively lower than the others. CONCLUSIONS : Based on our study, skid resistance of the pavement should be regarded as one of the pavement management system, so periodic measurement should be made to assure road safety as a whole.

• Corrosion Science and Technology
• /
• 제11권4호
• /
• pp.135-140
• /
• 2012

The linear polarization resistance method is one of the widely used techniques for the corrosion rate monitoring in the water circulating systems of plants. The measurement is simple and rapid, so that a continuous on-line monitoring is possible without any shutdown of plants. A 2-electrode polarization corrosion rate measurement system was installed in a laboratory using a data acquisition board and PC. The signal processing parameters were optimized for the accurate corrosion rate measurement, and the polarization resistance was compensated with the solution resistance measured by the high frequency sine wave signal of an output channel. The precision of corrosion rate data was greatly improved by removing the initial noise signals on measuring the polarization resistance.

• Composites Research
• /
• 제26권3호
• /
• pp.201-206
• /
• 2013

전기저항 측정법을 이용하여 전도성을 띄는 소재는 손상예측이 가능하다. 본 연구에서는 차량용 소재로 이용하는 폴리프로필렌(PP)를 이용할 때 재료 내부에 발생될 손상 평가법을 고안하였다. PP 내부에 전도성을 부여하기 위해 탄소나노튜브(CNT)를 0.5 wt% 삽입하여 CNT/PP 복합재료를 제조하였다. 손상 평가를 하기 위해 시편 내부에 구리선을 삽입하여 가로와 세로, 대각선 구간을 설정하여 측정하였다. 시편의 모형은 $20^{\circ}$ 휘어진 시편을 사용하였다. 동적 압축 실험에 따른 전기저항 측정을 통해 구간별로 전기저항 변화도를 분석하였다. 동적 압축 실험에 따른 구간별 전기저항 변화도의 신호는 재료 내부에 전가된 응력을 나타내는 신호이다. 전기저항 측정 구간에서 전기저항 변화도가 높은 경우는 미세 손상이 발생되었음을 의미한다. 전기저항 측정법을 이용한 동적 압축 실험에 따른 예상 손상부위와 실제 파괴 실험을 통해 본 평가 방법을 이용하여 재료 내부 미세 손상을 예측할 수 있는 방법임을 확인하였다.

• 대한치과교정학회지
• /
• 제18권2호
• /
• pp.289-308
• /
• 1988

The center of resistance is a important determining factor of tooth movement pattern. Laser speckle interferometry, recently developed for noninvasive measurement of small displacements (microns), was used to detect the center of resistance of a maxillary canine which has normal tooth axis and distal curved root in dry human skull. Laser holographic interferometry was used to verify the results of laser speckle interferometry The following result were obtained; 1. In measurement of the degree of rotation, center of resistance was localized when the traction line passed 4.4/18.0 level from alveola crest to root apex. 2. In measurement of the degree of tipping, center of resistance was localized when the traction line passed 4.6/18.0 level from alveola crest to root apex. 3. In holographic determination, the center of resistance was observed when the traction line passed between 3mm to 6mm level from alveola crest to root apex, therefore the results using laser speckle interferometry was coincided with holographic results.

• KEPCO Journal on Electric Power and Energy
• /
• 제6권1호
• /
• pp.35-40
• /
• 2020

The purpose of this paper is to improve the grounding point measurement method for the maintenance of the earth resistance of the distribution line. This study defines the correlation among humidity of the soil, the earth resistivity and the grounding resistance. Based on the results of the study, the grounding resistance value measurement should be limited to the location where the earth resistivity change is large, and the measurement time and cost can be greatly reduced.