A microfluidic system for the measurement of chemical concentration and density

Sparks, D.; Smith, R.; Straayer, M.; Cripe, J.; Schneider, R.; Massoud-Ansari, S.; Najafi, Nader

doi:10.1109/sensor.2003.1215312

Cited by 8 publications

(6 citation statements)

References 4 publications

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“…The cap is sealed to the glass wafer via wafer-to-wafer bonding. Fluid is admitted to the microtube through holes in the back of the metalized glass chip [1][2][3]. 3EF9.P…”

Section: Methodsmentioning

confidence: 99%

“…The MEMS-chip based density sensor has been used to test the concentration of sulfuric acid solutions, solvents and petrochemicals with no change in sensor performance [1]. Formic acid is a common DMFC by-product.…”

Section: Transducers and Eurosensors '07mentioning

confidence: 99%

“…1, which has been under developed specifically for the fuel cell chemical concentration market for over three years. This microfluidic technology has previously been used to measure fluid density, chemical concentration in a laboratory setting [1] and mass flow rate [2]. It uses a getter assisted, vacuum packaged [3], single crystal silicon resonating tube along with an integrated thin film RTD.…”

Section: Introductionmentioning

confidence: 99%

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Embedded MEMS-Based Concentration Sensor for Improved Active Fuel Cell Performance

Sparks

Riley

Cruz

et al. 2007

TRANSDUCERS 2007 - 2007 International Solid-State Sensors, Actuators and Microsystems Conference

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A MEMS-based methanol concentration sensor for monitoring and controlling the methanol to water ratio in a DMFC system is described. This sensor is based on a microfluidic chip that employs a resonant microtube and on-chip platinum temperature sensor to measure the density of a fluid. Using the density and temperature output the methanol concentration is determined. The performance of the sensor over temperature, concentration and in the presence of formic acid by-products is examined. Test comparisons between this sensing method and refractive index and speed-of-sound methanol concentration sensors are made. Additional biofuel applications for the sensor will be discussed.

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“…The cap is sealed to the glass wafer via wafer-to-wafer bonding. Fluid is admitted to the microtube through holes in the back of the metalized glass chip [1][2][3]. 3EF9.P…”

Section: Methodsmentioning

confidence: 99%

Section: Transducers and Eurosensors '07mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Embedded MEMS-Based Concentration Sensor for Improved Active Fuel Cell Performance

Sparks

Riley

Cruz

et al. 2007

TRANSDUCERS 2007 - 2007 International Solid-State Sensors, Actuators and Microsystems Conference

Self Cite

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“…Figure 18 shows a sensor that measures the density and flow rate of a small amount of liquid. 29) The sensor is realized by miniaturizing a Coriolis mass flow meter using MEMS technology and has been marketed by Integrated Sensing Systems Inc., USA. In the sensor, a U-shaped Si tubular resonator is electrostatically driven, and the density of the liquid can be obtained from the resonant frequency.…”

Section: Flow Sensorsmentioning

confidence: 99%

Revolution of Sensors in Micro-Electromechanical Systems

Esashi

2012

Jpn. J. Appl. Phys.

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Microsensors realized by micro-electromechanical systems (MEMS) technology play a key role as the input devices of systems. In this report, the following sensors are reviewed: piezoresistive and capacitive pressure sensors, surface acoustic wave (SAW) wireless pressure sensors, tactile sensor networks for robots, accelerometers, angular velocity sensors (gyroscopes), range image sensors using optical scanners, infrared imagers, chemical sensing systems as Fourier transform infrared (FTIR) spectroscopy and gas chromatography, flow sensors for fluids, and medical sensors such as ultrafine optical-fiber blood pressure sensors and implantable pressure sensors.

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“…To eliminate this drawback, in 2003 Sparks [28] presented a silicon capping wafer bonded to a glass wafer to form a micro vacuum chamber. To lower the vacuum pressure and minimize damping [29,30], this group added a getter (Nano Getter) to absorb gases which remained in the microcavity [6], as shown in Figure 3.9.…”

Section: Review Of Existing Fabrication Methods For a Micro-coriolis ...mentioning

confidence: 99%

Cylindrical tubes with large diameters and thin walls for application in microfluidic density and mass flow sensors

Yariesbouei

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In the past, numerous density and flow sensors have been presented for a large variety of applications such as the food, beverage, pharmaceutical, and petroleum industry. Over time, with emerging new applications such as gas chromatography, drug delivery, and biomedical applications, monitoring of very small flow rates, and detection of fluid composition have become even more important. Besides, in medical applications, there is a need for disposable sensors for avoiding contamination.Almost three decades ago, the first micromachined density and Coriolis mass flow sensor was introduced. This sensor was based on a freely suspended vibrating channel. Over the years, to improve the performance of the microfluidic sensor, different fabrication methods based on silicon micromachining techniques such as anisotropic wet and dry etching, polymer photolithography, and surface channel technology were proposed. All these fabrication methods lead to a freely suspended channel with a noncircular cross-sectional shape, such as hexagonal, rectangular, or semicircular, and a limited range of wall thicknesses and cross-sectional areas, which leads to a limited flow range and pressure dependency of the sensor. Besides, the ratio of the diameter to wall thickness should be increased to obtain a higher sensitivity to mass flow and fluid density. To overcome these drawbacks, this research aims to improve the range of channel diameters of a circular shape and a relatively thin, chemically inert channel wall.

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A microfluidic system for the measurement of chemical concentration and density

Cited by 8 publications

References 4 publications

Embedded MEMS-Based Concentration Sensor for Improved Active Fuel Cell Performance

Embedded MEMS-Based Concentration Sensor for Improved Active Fuel Cell Performance

Revolution of Sensors in Micro-Electromechanical Systems

Cylindrical tubes with large diameters and thin walls for application in microfluidic density and mass flow sensors

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