Simultaneous thermal conductivity and diffusivity sensing in liquids using a micromachined device

Kuntner, J.; Köhl, F.; Jakoby, Bernhard

doi:10.1016/j.sna.2005.11.021

Cited by 60 publications

(50 citation statements)

References 10 publications

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“…In the literature, we can find other thermal applications interested in measuring changes of temperature rather than the absolute value of temperature. For instance, the measurement of the amplitude (and also the phase shift) of temperature oscillations at a given frequency generated by the AC power dissipated by a heating element is used to determine thermal properties of fluids [14] and to monitor biofilm dynamics [15].…”

Section: On-chip Thermal Testing Techniquementioning

confidence: 99%

On-Chip Thermal Testing Using MOSFETs in Weak Inversion

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Altet

2015

IEEE Trans. Instrum. Meas.

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Abstract-This paper analyses the feasibility of using metal-oxide-semiconductor field-effect transistors (MOSFET) operating in weak inversion as temperature sensors for on-chip thermal testing applications. MOSFETs in weak inversion are theoretically analyzed so as to know how their sensitivity to temperature depends on both dimensions and bias current. Theoretical predictions are then compared with simulations and experimental data resulting from MOSFETs fabricated in a commercial 0.35 μm CMOS technology. MOSFETs are experimentally subjected to changes of temperature generated by either a heating chamber or an on-chip power dissipating device. The performance of MOSFETs in weak inversion is also compared with that in strong inversion and with that of parasitic bipolar junction transistors (BJT). In the context of on-chip thermal testing, MOSFETs in weak inversion offer advantages in terms of layout area, linearity, current consumption and spread of the sensitivity to temperature due to process variations.

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Section: On-chip Thermal Testing Techniquementioning

confidence: 99%

On-Chip Thermal Testing Using MOSFETs in Weak Inversion

Reverter

Altet

2015

IEEE Trans. Instrum. Meas.

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“…Dort sind sie oftmals als Herzstück von komplexen Mess-, Steuer-und Regelungssystemen für die Messsignalerfassung und -konversion der Messgröße in elektrisch quantifizierbare Signale zuständig. So werden sie etwa in 1. der molekularen Biotechnologie zur Flussüberwachung innerhalb von Durchflusszytometern [1], der Gebäude-und Reinraumtechnologie zur Steuerung von Klima-und Abluftanlagen [2], der Meteorologie zur Vermessung von Windrichtung und -stärke [3], 2. der Pulmologie zur Bestimmung der Wärmeleitfähigkeit in gaschromatographischen Atemgasanalysen [4], der Getränke-herstellung zur Stammwürzemessung in Bierbraukesseln sowie in Transformatoren und Kraftfahrzeugen zur Quantifizierung der Ölqualität eingesetzt [5,6]. [8].…”

Section: Introductionunclassified

Miniaturisierte thermische Fluidsensoren – Strömungs- und thermische Leitfähigkeitssensoren

Talic

Ćerimović

Köhl

et al. 2015

Elektrotech. Inftech.

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Sensoren zur Bestimmung der Eigenschaften von Flüssigkeiten und Gasen werden in vielen Bereichen der Mess-und Automatisierungstechnik zur direkten und indirekten Zustandsüberwachung eingesetzt. Dieser Beitrag stellt unterschiedliche Varianten robuster Sensoren zur Bestimmung von Strömungseigenschaften (Geschwindigkeit, Richtung und Strömungsmenge) und zur Vermessung von thermischen Materialparametern (thermische Leitfähigkeit und thermische Diffusivität) von Fluiden vor. Diese Sensoren basieren auf einem thermischen Funktionsprinzip und sind mit Mitteln der Mikrotechnologie kostengünstig herstellbar. Ausgehend von einem einzigen Basisdesign können sie als kalorimetrische Strömungssensoren oder als thermische Leitfähigkeitssensoren ausgeführt und betrieben werden. Im vorliegenden Beitrag werden die theoretischen Grundlagen erläutert und einige Anwendungsbeispiele diskutiert.Schlüsselwörter: Fluidsensorik; Kalorimetrische Strömungssensoren; Thermische Leitfähigkeit; Thermische Diffusivität Miniaturized thermal fluid sensors -Flow and thermal conductivity sensors.Sensors for the determination of fluid and gas properties are being employed for direct and indirect condition monitoring in many application areas of instrumentation and automation. This article presents various robust sensors devised to measure flow properties (velocity, direction, and mass flow) as well as thermal properties (thermal conductivity and diffusivity) of fluids. These sensors are based on a thermal operation principle and can be manufactured with cost-effective microtechnology. Starting from one generic design, they can be implemented and operated as calorimetric flow sensors or thermal conductivity sensors. This article explains the theoretical foundations and discusses several application examples.

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“…During the past two decades several efforts have been made to evaluate viscosity, mass density, permittivity, and thermal conductivity regarding their suitability as monitoring parameters (Jakoby and Vellekoop 2004;Kuntner et al 2006;Kuntner 2008;Beigelbeck et al 2011). While thermal conductivity measurements are traditionally utilized for gas sensing (e.g., gas chromatographs (Grob and Barry 2004)) and permittivity monitoring is commonly used in combination with capacitive-based readout mechanisms (e.g., fuel level indicators (Toth et al 1997;Shi et al 1991)), the focus of interest has clearly shifted to viscosity and mass density detection.…”

Section: Introductionmentioning

confidence: 99%

Sensing viscosity and density of glycerol–water mixtures utilizing a suspended plate MEMS resonator

et al. 2012

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A sensor suitable for online monitoring of viscosity and density of glycerol-water mixtures is presented. The device is based on Lorentz force excitation and features an integrated piezoresistive readout. The core sensing element is a rectangular vibrating plate suspended by four beam springs. Two of the plate-carrying springs comprise piezoresistors. With two additional resistors on the silicon rim they form a half Wheatstone-bridge. Through the conductive layer of the beam springs a sinusoidal excitation current is driven. In the field of a permanent magnet, the Lorentz force excites plate vibrations resulting in a bridge unbalance. We recorded both the frequency response of the amplitude and the phase of the bridge output. By evaluating the properties of the resonant system, it is possible to extract the glycerol percentage and, hence, the viscosity and the mass density of the mixtures. This work is an extended version of the paper originally presented at SPIE List of symbols

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Simultaneous thermal conductivity and diffusivity sensing in liquids using a micromachined device

Cited by 60 publications

References 10 publications

On-Chip Thermal Testing Using MOSFETs in Weak Inversion

On-Chip Thermal Testing Using MOSFETs in Weak Inversion

Miniaturisierte thermische Fluidsensoren – Strömungs- und thermische Leitfähigkeitssensoren

Sensing viscosity and density of glycerol–water mixtures utilizing a suspended plate MEMS resonator

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