• Structural Monitoring and Maintenance
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• 제3권4호
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• pp.335-347
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• 2016

One of major errors in flow rate measurement for two-phase flow using an Electrical Capacitance Sensor (ECS) concerns sensor sensitivity under temperature raise. The thermal effect on electrical capacitance sensor (ECS) system for air-water two-phase flow monitoring include sensor sensitivity, capacitance measurements, capacitance change and node potential distribution is reported in this paper. The rules of 12-electrode sensor parameters such as capacitance, capacitance change, and change rate of capacitance and sensitivity map the basis of Air-water two-phase flow permittivity distribution and temperature raise are discussed by ANSYS and MATLAB, which are combined to simulate sensor characteristic. The cross-sectional void fraction as a function of temperature is determined from the scripting capabilities in ANSYS simulation. The results show that the temperature raise had a detrimental effect on the electrodes sensitivity and sensitive domain of electrodes. The FE results are in excellent agreement with an experimental result available in the literature, thus validating the accuracy and reliability of the proposed flow rate measurement system.

• 한국생산제조학회지
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• 제8권4호
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• pp.29-37
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• 1999

This paper involves the "on-line" measurement of burrs using a capacitance sensor. A non-contact capacitance gauging sensor is attached to an ultra precision milling machine which was used as a positioning system The setup is used to measure burr profiles along machined workpiece edges. Experimental procedures and results as well as the basic theoretical principles of the capacitance sensor and specifications of related equipment are presented. The proposed scheme is shown to be accurate easy to setup and with minor modifications readily applicable to automatic deburring processes.processes.

• 한국응용과학기술학회지
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• 제24권4호
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• pp.377-382
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• 2007

We designed capacitance sensor in order to examine characteristics of W/O type emulsified fuel, so it concluded the following conclusions. The capacitance value of emulsified fuel, using with capacitance sensor, increases as water content increases due to the coalescence. When surfactant increases, the capacitance value decreases, the condition of W/O type emulsified fuel was maintained stably. There was revealed the capacitance value difference of W/O type emulsified fuel in in according to water content. We checked the phase separation of emulsified fuel with the capacitance value difference. The surfactant(HLB=5.4) had better stable condition than surfactant(HLB=4.3). Also, we confirmed that two mixture surfactants were better than one surfactant.

• 한국토양비료학회지
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• 제44권3호
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• pp.331-336
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• 2011

최근 편리함과 측정의 정확성으로 인해 Capacitance sensor가 토양수분 연구나 물관리에 국제적으로도 널리 이용되고 있다. 이 연구는 Capacitance sensor (EnviroSCAN, Sentek Ltd.)가 화산회토양이 많이 분포하는 제주도 지역에서도 활용성이 있는 지를 알아보기 위해 유기물함량이 다른 제주도의 대표적인 토양 종류를 이용하여 Calibration 시험을 수행하였다. 시험 결과 화산회토양에서는 비화산회토양과 달리 센서의 Scaled frequency와 토양의 용적수분함량 간에 Calibration식이 로그식 형태로 나타내는 것이 일반적으로 적용되는 지수식 형태로 나타내는 것보다 상관이 더 높게 나타났다. 또한 화산회토양이 많이 분포하는 지역에 서는 토양수분함량이 높아 습하거나 매우 적어 건조할 경우에는 Capacitance sensor에 의한 수분함량 측정값이 건조기를 이용한 수분함량 값보다 과소하게 측정될 수 있었다. Capacitance sensor를 이용하여 화산회토양에서 토양 수분함량을 정확하게 측정하기 위해서 Calibration식에 적용될 수 있는 현실적인 계수값을 제시하였다. 또 현재 이용되는 EnviroSCAN capacitance probes의 활용성을 제고하기 위해서 계수값을 유기물함량별로 추정하는 식을 제시 하였다. Capacitance sensor를 이용하여 토양수분함량을 정확하게 측정하기 위해서는 사전에 토양의 공극분포, 유기물함량, EC 등 측정여건을 파악하여 조절하는 것이 필요하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.317-322
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• 1994

The design and performance verification of collocated capacitance sensor system for magnetic bearing is presented. Noncollocation between actuators and sensors may cause unstable rotor behavior. The capacitance sensor is not affected by magnetic field. PCB type capacitance sensor is installed between magnetic bearing polse. so, collocation of sensors and actuators can be achieved. Experiment of sensor's static and dynamic charactistics is conducted. Modeling of the rotor system supported by magnetic bearing is made. And performance comparison between simulation and experiment is showed.

• 한국염색가공학회지
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• 제31권2호
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• pp.65-76
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• 2019

A multi-point touch input sensor having different sizes or different capacitance touch points connected by only one pair of signal transmission lines was fabricated using a polyimide film coated with a thin copper plate. The capacitance increases with the decrease in the number of sheets of fabric spacers placed between the two sheets of the polyimide film. Therefore, the touch input sensor could be manufactured without fabric spacers, which was possible by the action of the polyimide film as a dielectric material in the capacitor. On the multi-point touch sensor, higher capacitance was obtained when pressing wider-area touch points with 10mm to 25mm diameter on average. However, the capacitance of a system comprising two sheets of touch sensors was considerably low, causing a serious overlap of the capacitance values according to the data collected from the reliability test. Although the capacitance values could be increased by stacking several sheets of touch sensors, the overlap of data was still observed. After reducing the size of all touch points to 10mm and stacking up to eight sheets of sensors, reliable and consistent capacitance data was obtained. Five different capacitance signals could be induced in the sensors by pushing touch points simultaneously.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.337-338
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• 2014

In this study, a method of using a capacitance sensor was investigated as a means to measure the mass fraction of a type of harmful substance. Using MEMS process, we developed a capacitance sensor and studied the real time mass fraction with harmful substance mixture liquid.

• 한국의류산업학회지
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• 제16권1호
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• pp.145-152
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• 2014

The usage of textile-based sensors has increased due to their many advantages (compared to IT sensors) when applied to body assessment and comfort. Textile-based sensors have different detecting factors such as pressure, voltage, current and capacitance to investigate the characteristics. In this study, textile-based sensor fabrics with sheath-core type conductive yarns were produced and the relationship between capacitance changes and applied load was investigated. The physical and electric properties of textile-based sensor fabrics were also investigated under various laminating conditions. A textile based pressure sensor that uses a sheath-core conductive yarn to ensure the stability of the pressure sensor in the textile-based sensor (the physical structure of the reaction characteristic of the capacitance) is important for the stability of the initial value of the initial capacitance value outside the characteristic of the textile structural environment. In addition, a textile based sensor is displaced relative to the initial value of the capacitance change according to pressure changes in the capacitance value of the sensor due to the fineness of the high risk of noise generation. Changing the physical structure of the fabric through the sensor characteristic of the pressure sensor via the noise generating element of laminating (temperature, humidity, and static electricity) to cut off the voltage output element to improve the data reliability could be secured.

• Structural Monitoring and Maintenance
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• 제3권3호
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• pp.297-314
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• 2016

As the study of internal corrosion of pipeline need a large number of experiments as well as long time, so there is a need for new computational technique to expand the spectrum of the results and to save time. The present work represents a new non-destructive evaluation (NDE) technique for detecting the internal corrosion inside pipeline by evaluating the dielectric properties of steel pipe at room temperature by using electrical capacitance sensor (ECS), then predict the effect of pipeline environment temperature (${\theta}$) on the corrosion rates by designing an efficient artificial neural network (ANN) architecture. ECS consists of number of electrodes mounted on the outer surface of pipeline, the sensor shape, electrode configuration, and the number of electrodes that comprise three key elements of two dimensional capacitance sensors are illustrated. The variation in the dielectric signatures was employed to design electrical capacitance sensor (ECS) with high sensitivity to detect such defects. The rules of 24-electrode sensor parameters such as capacitance, capacitance change, and change rate of capacitance are discussed by ANSYS and MATLAB, which are combined to simulate sensor characteristic. A feed-forward neural network (FFNN) structure are applied, trained and tested to predict the finite element (FE) results of corrosion rates under room temperature, and then used the trained FFNN to predict corrosion rates at different temperature using MATLAB neural network toolbox. The FE results are in excellent agreement with an FFNN results, thus validating the accuracy and reliability of the proposed technique and leads to better understanding of the corrosion mechanism under different pipeline environmental temperature.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.291-295
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• 1996

This paper discusses several design factors of a capacitance displacement sensor with a numerical method and several experiments and describes guide lines of the design of this type sensor. We introduce the charge density method for the analysis of this type sensor, which has feasible accuracy and efficiency. The analysis of this type sensor with the charge density method agrees with displacement sensitivity experiments of a circular plate capacitance sensor with the sensor amp based In the charge transfer principle.