• Title/Summary/Keyword: measurement resistance

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Measurement Criteria for Drag-Sled Type Slip Resistance Tester Based on Human Gait and Slip (인간의 보행 및 미끄러짐 특성에 기반한 끌기형 미끄러짐 저항 측정 조건)

  • Park, Jae-Suk;Kwon, Hyuck-Myun;Oh, Whan-Sup
    • Journal of the Korean Society of Safety
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    • v.27 no.5
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    • pp.179-184
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    • 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.

Development of Measurement System for Quantitative Measurement of Cantilever in Atomic Force Microscopy (원자간격 현미경의 캔틸레버의 정량적 특성평가를 위한 계측 시스템 개발)

  • Kweon, Hyun-Kyu;Nam, Ki-Ho
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.6 no.2
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    • pp.22-27
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    • 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.

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Resistive displacement transducer enhanced measurement resolution by electrical line contact (선형 전기접촉으로 계측해상도가 향상된 저항성 변위센서)

  • Kim, Kyung-Ah;Choi, Seong-Su;Cha, Eun-Jong
    • Journal of Sensor Science and Technology
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    • v.16 no.4
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    • pp.263-269
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    • 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.

A Study on the Improvement of Water-Leakage Detection Reliability in Local Heating System (지역난방배관의 누수감지 신뢰성 향상에 관한 연구)

  • 신춘식;안영주;변기식
    • Journal of the Korean Society of Safety
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    • v.14 no.1
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    • pp.66-72
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    • 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.

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A Study on the Measurement Technique of the Grounding Mesh Resistance by Field Measurements (현장실측에 의한 메시(Mesh)접지저항 출정기법 연구)

  • 한기붕;김삼수;정세중;이상익
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.426-429
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    • 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.

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Skid Resistance Characteristics of Pavement Surface (포장노면 미끄럼 저항특성)

  • Kim, Yong-Seok;Hong, Jae-Cheong;You, Hyeong-Mok
    • International Journal of Highway Engineering
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    • v.14 no.4
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    • pp.1-8
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    • 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.

Study on an On-line Measurement System of Corrosion Rate by Linear Polarization Resistance (분극저항에 의한 온라인 부식속도 측정 시스템에 관한 연구)

  • Moon, Jeon Soo;Lee, Jae Kun;Lee, Jae Bong;Park, Pyl Yang
    • Corrosion Science and Technology
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    • v.11 no.4
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    • pp.135-140
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    • 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.

Electrical Resistance Measurement in Characterizing the Internal Damage of Carbon Nanotube/Polypropylene Nanocomposites (전기저항 측정법을 이용한 탄소나노튜브/폴리프로필렌 나노복합재료의 내부 손상 예측)

  • Kim, Hak-Soo;Kwon, Dong-Jun;Wang, Zuo-Jia;Gu, Ga-Young;Kim, Dae-Sik;Lee, Chun-Soo;Park, Joung-Man
    • Composites Research
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    • v.26 no.3
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    • pp.201-206
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    • 2013
  • The electrical resistance measurement was investigated as a damage monitoring method. In this study, 0.5 wt% Carbon nanotube reinforced polypropylene (CNT/PP) composites were evaluated under compressive fatigue loading. The shape of specimens was $20^{\circ}$ curved round type. Compression strength and electrical resistance were measured at different sections of specimen during compression. The microcracks of CNT/PP composites were detected based on the changing ratio of electrical resistance. Micro-damage during compressive fatigue test could be detected by electrical resistance measurements. The reason is that the contact points of CNTs in composites decreased under fatigue loading. During compressive fatigue test, larger change of electrical resistance was detected at the microcrack sections. It was proved that microcracks could be detected by electrical resistance measurement under compression test, whereas the real delamination parts were consistent with the predicted results by electrical resistance measurement.

EXPERIMENTAL STUDY OF THE CENTER OF RESISTANCE OF A MAXILLARY CANINE USING LASER SPECKLE INTERFEROMETRY AND HOLOGRAPHIC INTERFEROMETRY (상악 견치의 저항 중심에 관한 Laser speckle interferometry와 holographic interferometry볼 이용한 실험적 연구)

  • Lee, Soo Ryong
    • The korean journal of orthodontics
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    • v.18 no.2
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    • pp.289-308
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    • 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.

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Estimation of Grounding Resistance by Correlation Analysing Change Factors of Soil Resistivity and Grounding Resistance (토양환경 변화와 접지저항의 상관관계 분석을 통한 접지 저항값 예측 연구)

  • Choi, Sun-Kyu;Lee, Kyu-Young;Moon, Young-Ho;Shim, Keon-Bo
    • KEPCO Journal on Electric Power and Energy
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    • v.6 no.1
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    • pp.35-40
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    • 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.