• 제목/요약/키워드: MFC sensor

검색결과 35건 처리시간 0.026초

Damage state evaluation of experimental and simulated bolted joints using chaotic ultrasonic waves

  • Fasel, T.R.;Kennel, M.B.;Todd, M.D.;Clayton, E.H.;Park, G.
    • Smart Structures and Systems
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    • 제5권4호
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    • pp.329-344
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    • 2009
  • Ultrasonic chaotic excitations combined with sensor prediction algorithms have shown the ability to identify incipient damage (loss of preload) in a bolted joint. In this study we examine a physical experiment on a single-bolt aluminum lap joint as well as a three-dimensional physics-based simulation designed to model the behavior of guided ultrasonic waves through a similarly configured joint. A multiple bolt frame structure is also experimentally examined. In the physical experiment each signal is imparted to the structure through a macro-fiber composite (MFC) patch on one side of the lap joint and sensed using an equivalent MFC patch on the opposite side of the joint. The model applies the waveform via direct nodal displacement and 'senses' the resulting displacement using an average of the nodal strain over an area equivalent to the MFC patch. A novel statistical classification feature is developed from information theory concepts of cross-prediction and interdependence. This damage detection algorithm is used to evaluate multiple damage levels and locations.

식물-미생물전기화학 기반의 미활용 에너지 회수 기초 연구 (Basic Study for Harvesting Unused Energy based on Plant-Microbial Electrochemical Technology)

  • 유재철;신춘환
    • 한국환경과학회지
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    • 제28권2호
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    • pp.219-224
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    • 2019
  • In this study, we evaluated the energy production from plant-microbial fuel cells using representative indoor plants, such as Scindapsus aureus and Clatha minor. The maximum power density of microbial fuel cell (MFC) using S. aureus ($3.36mW/m^2$) was about 2 times higher than that of the MFC using C. minor ($1.43mW/m^2$). It was confirmed that energy recovery is possible using plant-MFCs without fuel. However, further research is needed to improve the performance of plant-MFCs. Nevertheless, plant-MFCs have proved their potential as a novel energy source to overcome the limitations of the conventional renewable energy sources such as wind power and solar cells, and could be employed to a power source for the sensor in charge of the fourth industrial revolution.

가정용 연료전지 시스템 내부 수소 누출 시 센서 응답 특성에 관한 연구 (A experimental study on the sensor response at hydrogen leakage in a residential fuel cell system)

  • 김영두;신동훈;정태용;남진현;김영규
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회B
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    • pp.2009-2014
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    • 2007
  • Hydrogen is a fuel of fuel cell system, which has powerful explosion possibility. Hence, the fuel cell system needs safety evaluation to prevent risk of hydrogen leakage. We use a actual size chamber of a common fuel cell module to analyze hydrogen. Hydrogen injection holes are located in lower part of the chamber in order to simulated hydrogen leakage. The hydrogen sensor can detect range of 0${\sim}$4%. Since the hydrogen gas, of which leaked amount is controled by MFC, are injected at the bottom holes, the transient sensor signals are measured. At a condition of 10cc/s of hydrogen leakage, the sensor detects hydrogen leakage after 22sec and there is also several seconds of time delay depending on the position of the sensor. This experimental data can be applied for the design of the hydrogen detection system and ventilation system of a residential fuel cell system.

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반도체 공정용 차압식 질량 유량 제어 장치의 개발 및 성능 평가 (Development and Evaluation of Differential Pressure Type Mass Flow Controller for Semiconductor Fabrication Processing)

  • 안진홍;강기태;안강호
    • 반도체디스플레이기술학회지
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    • 제7권3호
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    • pp.29-34
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    • 2008
  • This paper describes the fabrication and characterization of a differential pressure type integrated mass-flow controller made of stainless steel for reactive and corrosive gases. The fabricated mass-flow controller is composed of a normally closed valve and differential pressure sensor. A stacked solenoid actuator mounted on a base-block is utilized for precise and rapid control of gas flow. The differential pressure flow sensor consisting of four diaphragms can detect a flow rate by deflection of diaphragm. By a feedback control from the flow sensor to the valve actuator, it is possible to keep the flow rate constant. This device shows a fast response less than 0.3 sec. Also, this device shows accuracy less than 0.1% of full scale. It is confirmed that this device is not attacked by toxic gas, so the integrated mass-flow controller can be applied to advanced semiconductor processes which need fine mass-flow control corrosive gases with fast response.

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반도체 제조장비용 챔버 가스누출 방지를 위한 제어모듈 개발 (Controller for Gas Leakage Protection in Semiconductor Process Chamber)

  • 박성진;이의용;설용태
    • 한국산학기술학회논문지
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    • 제6권5호
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    • pp.373-377
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    • 2005
  • 본 논문에서는 반도체 제조장비의 챔버 내부 가스누출을 방지하기위한 보완모듈을 제시하였다. MFC(mass flow controller) 다음단의 최종밸브와 챔버 사이의 가스관에 압력센서를 부착시켜, 압력센서의 신호와 최종밸브의 동작신호를 디지털 회로를 이용하여 실시간으로 감지하고 가스누출을 방지하도록 하였다. LED 모듈을 이용하여 공정중에 발생하는 2차 소성물로 인한 가스의 흐름과 관련된 시스템 고장을 표시한다. 본 연구에서 개발한 모듈을 이용하면 챔버 내에서의 가스누출로 인한 장비의 손상과 안전사고 등을 예방하는 효과가 있다.

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Sensing characteristics of Polypyrrole-based methanol sensors preparedbyin-situ vapor state polymerization

  • Linshu Jiang;Jun, Hee-Kwon;Hoh, Yong-Su;Lee, Duk-Dong;Huh, Jeung-Soo
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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    • pp.137-137
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    • 2003
  • Conducting PPy/PVA composite and pure PPy gas sensors were prepared by in-situ vaporstate polymerization method in a vaporization chamber under N2 condition, by exposing the pre-coated electrode with PVA/FeC13 to distilled pyrrole monomer. The various electrical sensing behaviors of both types of sensors were systematically investigated by a flow measuring system including mass flow controller (MFC) and bubbling bottle. The FT-Raman spectroscopy of vapor state polymerized PPy was identical to that of chemically polymerized PPy, confirming the same chemical structure. Both types of sensors had positive sensitivity when exposed to methanol gas. The sensitivity varied linearly with gas concentration in the range of 50ppm to 1059ppm. The detection limit of PPy/PVA sensor was believed to be as low as 10ppm. The sensitivity of PPy/PVA composite sensor was higher than that of pure PPy sensor. Both the response time and recovery time of PPy/PVA composite sensors were longer than those of pure PPy sensors. The thickness of the sensing film affected the sensitivity this way that the sensor having thinner film had higher sensitivity, indicating that the resistance of polymer film involved in the sensing behavior was bulk resistance rather than surface resistance. The reproducibility of PPy/PVA composite sensor was excellent during eight on-off cycles by switching between N2 and 3000ppm methanol gas. The sensitivity of PPy/PVA composite sensor was only maintained for two weeks, while the sensitivity of pure PPy sensor was maintained over two months.

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가정용 연료전지 시스템 내부 수소 누출 시 센서 응답 특성에 관한 연구 (An Experimental Study on the Sensor Response at Hydrogen Leakage in a Residential Fuel Cell System)

  • 김영두;신동훈;정태용;남진현;김영규;이정운
    • 한국수소및신에너지학회논문집
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    • 제20권5호
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    • pp.378-383
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    • 2009
  • Hydrogen is the primary fuel in fuel cell systems. Because of high inflammation and explosion possibility of hydrogen, fuel cell systems require safety measures to prevent hydrogen hazard upon leakage. In this study, a model enclosure was made by referring to a commercial residential fuel cell system and hydrogen leakage experiments and computational simulations were conducted therein. Hydrogen was injected into the cavity through leakage holes located at the bottom while its flow rate was precisely controlled using MFC. The transient sensor signals from hydrogen sensors installed inside the enclosure were recorded and analyzed. The hydrogen sensor signals showed different delay times depending on their position relative to a leakage point, which indicated that hydrogen generally moves upward and accumulates at the upper region of a closed cavity. The inflammable regions with hydrogen concentration over 4% LEL were observed to locate near the leakage hole initially, and broaden towards the upper cavity region afterward. The simulation result showed that detection time at the hydrogen sensor was similar to the pattern of experimental results. However, the maximum concentration of hydrogen had a gap between experiment and simulation at detect point due to measurement errors and reaction rate.

다양한 크기의 지도에 대응 가능한 위치 및 거리 감지 GPS신호 변환 알고리즘 구현 (A new algorithm for GPS signal transformation with location and distance sensing capability for various sizes of maps)

  • 정하연;손영호
    • 센서학회지
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    • 제18권1호
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    • pp.22-27
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    • 2009
  • The GPS(global positioning system) made up of 28 artificial satellites going round around the earth at a height of 20,000.Km is a system to determine the receiver's location by measuring the distance between the satellite and receivers using an electronic wave. Recently it's been widely used in various applications, such as a navigator, a surveying system, etc. In this paper, we propose a new algorithm to transform coordinates from GPS signals corresponding to various sizes of maps, and the application using this algorithm is also introduced. The algorithm is programmed by MFC on the WinCE 5.0 operating system, and the GPS receiver with a 20 channel high sensitivity and GPS microcontroller chip manufactured by SiRF Technology was used.

Remote Impedance-based Loose Bolt Inspection Using a Radio-Frequency Active Sensing Node

  • Park, Seung-Hee;Yun, Chung-Bang;Inman, Daniel J.
    • 비파괴검사학회지
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    • 제27권3호
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    • pp.217-223
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    • 2007
  • This paper introduces an active sensing node using radio-frequency (RF) telemetry. This device has brought the traditional impedance-based structural health monitoring (SHM) technique to a new paradigm. The RF active sensing node consists of a miniaturized impedance measuring device (AD5933), a microcontroller (ATmega128L), and a radio frequency (RF) transmitter (XBee). A macro-fiber composite (MFC) patch interrogates a host structure by using a self-sensing technique of the miniaturized impedance measuring device. All the process including structural interrogation, data acquisition, signal processing, and damage diagnostic is being performed at the sensor location by the microcontroller. The RF transmitter is used to communicate the current status of the host structure. The feasibility of the proposed SHM strategy is verified through an experimental study inspecting loose bolts in a bolt-jointed aluminum structure.

열전대 센서와 압전체 구동기가 부착된 유량제어기의 DC 이득과 시상수를 이용한 제어에 대한 연구 (A Study for Control using DC Gain and Time Constant of Flow Controller Operated by Piezoelectric Actuator and Thermocouple)

  • 이상경;김영수
    • 한국기계가공학회지
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    • 제3권1호
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    • pp.79-83
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    • 2004
  • This study was how to control the mass flow controller in gas supplying system. The flow controller consists of piezoelectric material and sensor with heating wire. It is difficult to obtain accurate model, because MFC was composed of many parts, and the relationship between input and output of controller is nonlinear. The model for control was obtained by time constant and DC gain Based on this model, PID controller was applied to flow controller using DSP board. Also, the results were compared to controller using system identification.

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