• Journal of Ocean Engineering and Technology
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• v.13 no.3 s.33
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• pp.100-107
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• 1999

Due to the high temperature and pressure, the materials of pipeline in power plant are degraded by creep damage. So far, many conventional measurement techniques such as replica method, electric resistance method, adn hardness test method for creep damage have been used. Among them, the replica method has mainly been used for the inspection of components. But this technique is restricted to the applications at the surface of the objects and cannot be used to material inside. In this paper, the measuring methods of evaluation by using ultrasonic attenuation and electric resistance for the creep detection of creep damage in the form of cavities on grain boundaries or intergranular microcracks were carried out. Absolute measuring method of quantitave ultrasonic attenuation technique for 1Cr0.5Mo material degradation was analyzed for determining the creep degradation steps using life prediction formula. As a result of measurement for creep specimens, we founded that the coefficient of utrasonic attenuation was increased as the increase of creep life fracton(${phi}c$) and the decreasing rate of wlwctric resistance was also increased.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.2
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• pp.222-231
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• 2010

This paper presents numerical analysis of measurement errors of ground electrode using the fall-of-potential method. In order to analyze ground resistance error according to the positions of auxiliary probes, firstly, national and international standards were researched. Secondly, numerical ground resistance error of hemispheric electrode was analyzed according to the locations of auxiliary probes and the angle between probes. Then, error-reduced positions of auxiliary probes were shown according to the distance to auxiliary current probe versus ground electrode size. Finally, error compensation method was presented. The results presented in this paper provide useful information regarding ground resistance error of alternative positions of auxiliary probes in case that the auxiliary probes could not be located at the proper position in such cases as there are buildings, roadblock or underground metallic pipe at that position.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.129-135
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• 2022

Currently, the rapid growth of electric vehicles and the collection and disposal of waste batteries are becoming a social problem. The purpose of this paper is to propose a fast and efficient battery screening method through a safe inspection and storage method according to the collection and storage of waste batteries of electric vehicles. In addition, as the resistance inside the waste battery increases, an instantaneous voltage drop occurs, and there is a risk of overcharging and overdischarging compared to the initial state of the battery. Accordingly, there are great difficulties in operation, so the final goal of this study is to develop a device for diagnosing aging through real-time battery internal resistance measurement. Final result As a result of simulation of the internal resistance measurement test circuit through external impedance (AC), the actual simulation value was 0.05Ω, RS = Vrms / Irms => Vrms = 8.0036mV, Irms = 162.83Ma. Substitute the suggested method. The result was calculated as Rs = 0.0495Ω. It is possible to measure up to 64 impedances inside the aging diagnostic equipment that enables real-time monitoring of the developed battery cells, and the range can be changed according to the application method.

• Journal of Korean Society of Steel Construction
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• v.8 no.3 s.28
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• pp.47-54
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• 1996

Recently Sucessive progress in train technic has enabled us to constructed high-speed railways for ourselves. This caused more rapid train more pressure on a track and speedier track break-down. Especially in the construction of high-speed rails for high-speed traveling and safety accurate breaking distance is essential and not only computation of rolling resistance in theory but also verification through real measurement are important in basic material for breaking and starting load caused during the train running. In this study, we measured traveling resistance and calculated traveling resistance formula in the case of the SAEMA-EUL which consists of main part of current passenger trains and frights in this country.

• Journal of Sensor Science and Technology
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• v.14 no.4
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• pp.231-236
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• 2005

Calibration capability was evaluated using the reference-grade platinum resistance thermometer (PRT) in the temperature range of $-50^{\circ}C$ to $250^{\circ}C$ for the national calibration centers. The reference-grade PRT was calibrated at the several fixed points, which was composed by the freezing points of Sn, In, the melting point of Ga and the triple point of water and Hg, before and after the round-robin test (RRT) experiments. The temperature scale of reference-grade PRT was compared to the local standard PRT's using the system of the national calibration centers. $E_{n}$ values was calculated by the temperature difference between the reference-grade PRT and the local standard PRT, and the best measurement capability. Finally, the capability of the national calibration centers was evaluated by the $E_{n}$ values.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.65-71
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• 2019

Conventional methods of measuring ground resistance and ground resistance field measurement are used to measure voltage drop according to the resistance value of the site by applying current by installing a constant interval of measurement electrode. If the stratified structure of the site site is unique, errors in boundary conditions will occur in the event of back acid and the analysis of the critical ground resistance in the ground design will show much difference from simulation. This study utilizes the Arduino module and smart ground measurement technology in the convergent information and communication environment to develop a reliable smart land resistance measuring device even if the top layer of land is unique, to analyze the land resistance and accumulate data to predict the change in the age of the land. Considering the topographical characteristics of the site, we propose a ground resistance measuring device and its method of measuring ground resistance so that the auxiliary electrode can be installed by correctly positioning the angle and distance in measuring ground resistance. Not only is ground resistance value obtained through electrodes installed to allow accurate ground resistance values to be selected, but it can also be used as a useful material for installing electrical facilities in similar areas. Moreover, by utilizing reliable data and analyzing the large sections of the site, a precise analysis of the site, which is important in ground design as well as construction cost, is expected to be used much in ground facility design such as potential rise.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.9
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• pp.470-474
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• 2004

Both ratio error and phase angle error in voltage transformer(VT) depend on values of burden of VT used. A method of evaluation for linearity of ratio error and phase angle error in VT measurement equipment have been developed using the standard resistance burdens, with negligible AC-DC resistance difference less than $10^-6$. These burden consists of five standard resistors, with nominal resistance of 100 $\Omega$, 1 k$\Omega$, 10 k$\Omega$, 100 k$\Omega$, and 1 M$\Omega$. The developed method has been applied in VT measurement equipment of industry and the validity of the developed method has been verified by showing the consistency of the result of linearity obtained using VT with wide ratio error.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.544-548
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• 2008

Typically electronic resistance type sensors have been used for measurement system of high-speed trains. But due to a large number of measurement quantities, we had difficulties in installing and maintaining the cables that connect sensors and measuring devices. Furthermore, signals obtained from the electronic resistance type sensors are often distorted because the sensors and cables are vulnerable to electro-magnetic interference (EMI). In this paper the characteristic of FBG sensors are compared with those of electronic resistance type sensors in application for the measurement system of high-speed trains. FBG sensors have advantages because of their multiplexing characteristic and robustness to EMI environment.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.4
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• pp.323-330
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• 2009

The objective of this research was to develop a practical integrated approach using extracted features from electrical resistance measurements and coupled electromechanical models of damage, for in-situ damage detection and sensing in carbon fiber reinforced plastic(CFRP) composites. To achieve this objective, we introduced specific known damage (in terms of type, size, and location) into CFRP laminates and established quantitative relationships with the electrical resistance measurements. For processing of numerous measurement data, an autonomous data acquisition system was devised. We also established a specimen preparation procedure and a method for electrode setup. Coupon and panel CFRP laminate specimens with several known damage were tested. Coupon specimens with various sizes of artificial delaminations obtained by inserting Teflon film were manufactured and the resistance was measured. The measurement results showed that increase of delamination size led to increase of resistance implying that it is possible to sense the existence and size of delamination. A quasi-isotropic panel was manufactured and electrical resistance was measured. Then three different sizes of holes were drilled at a chosen location. The panel was prepared using the established procedures with six electrode connections on each side making a total of twenty-four electrodes. Vertical, horizontal, and diagonal pairs of electrodes were chosen and the resistance was measured. The measurement results showed the possibility of the established measurement system for an in-situ damage detection method for CFRP composite structures.

• Journal of environmental and Sanitary engineering
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• v.17 no.1
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• pp.28-35
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• 2002

A methods of minimizing the measurement error brought from gas compositions was proposed by Hot wire Anemometer which don't have measurement resistance to calculate of gas vent in sanitary landfill. It was determined measurement error to compared velocity at the center of pipe to calculate using rotor meter and density gas compositions with velocity at the center of pipe to calculate using water head indicator which don't have measurement resistance. Considering the methods of minimizing gas velocity in sanitary landfill using hot wire anemometer and rotor meter, it was found to minimize within 10% as error of gas vent in sanitary landfill.