Binary MEMS gas sensors

Khater, Mahmoud; Al‐Ghamdi, Majed; Park, Sangtak; Stewart, Katherine M. E.; Abdel‐Rahman, Eihab; Penlidis, Alexander; Nayfeh, Ali H.; Abdel-Aziz, Ahmad; Basha, Mohammad Abd Alkhalik

doi:10.1088/0960-1317/24/6/065007

Cited by 32 publications

(40 citation statements)

References 23 publications

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“…One of the most common types of bifurcation sensors is a mass sensor, which uses the shifting natural frequency from the added mass of the sensed particle to induce a dramatic jump in the sensor response when the particle count passes a threshold [6], [7]. Other types of bifurcations that have been used for sensing are bi-stability [8], and the pull-in instability [9], [10]. Pull-in bifurcation sensors are particularly useful for a MEMS pressure switch because their bifurcation is associated with two conductors coming into contact with each other, which can be seen as the closing of a switch.…”

Section: Introductionmentioning

confidence: 99%

A Tunable Electrostatic MEMS Pressure Switch

Pallay

Miles

Towfighian

2020

IEEE Trans. Ind. Electron.

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We demonstrate a tunable air pressure switch. The switch detects when the ambient pressure drops below a threshold value and automatically triggers without the need for any computational overhead to read the pressure or trigger the switch. The switch exploits the significant fluid interaction of a MEMS beam undergoing a large oscillation from electrostatic levitation to detect changes in ambient pressure. If the oscillation amplitude near the resonant frequency is above a threshold level, dynamic pullin is triggered and the switch is closed. The pressure at which the switch closes can be tuned by adjusting the voltage applied to the switch. The use of electrostatic levitation allows the device to be released from their pulledin position and reused many times without mechanical failure. A theoretical model is derived and validated with experimental data. It is experimentally demonstrated that the pressure switching mechanism is feasible.

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Section: Introductionmentioning

confidence: 99%

A Tunable Electrostatic MEMS Pressure Switch

Pallay

Miles

Towfighian

2020

IEEE Trans. Ind. Electron.

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“…However, depending on the architecture of the capacitive sensor, a conductive polymer might short circuit the sensor, and thus a conductive polymer cannot be used as a sensing material for that type of sensor . For a mass‐based sensor, such as a micro‐cantilever, a light sensing material is required, such as a polymer instead of a metal or metal oxide …”

Section: Selecting Sensing Materialsmentioning

confidence: 99%

Designing Polymeric Sensing Materials for Analyte Detection and Related Mechanisms

Stewart

Penlidis

2016

Macromolecular Symposia

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Summary:A systematic approach is used to design and tailor sensing materials for targeted analytes and specific applications. An example is used to demonstrate how potential sensing materials can be designed based on the chemical nature of both the target analyte and the sensing material, and thus predominant sensing mechanisms by which the two interact. The example analyte is a small, polar molecule able to hydrogen bond; therefore, a sensing material that targets the analyte should have polymer chains that pack tightly together, be polar, and be able to hydrogen bond. Any metal oxide dopants should be able to coordinate to both the target analyte and the polymer. Polyaniline and poly (o-anisidine), along with nickel oxide and zinc oxide, are chosen as potential sensing materials and subsequently evaluated based on their ability to sorb the analyte in question.

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“…Recently, great attention has been devoted to the development of robust and sensitive microscale bifurcation-based sensors due to the ease of activating strongly nonlinear behaviors on such a length scale, including the pitchfork [38][39][40] and saddle-node bifurcations [41][42][43][44]. By leveraging unmistakable and sudden variations in sensor behavior due to subtle perturbations to the system which induce the bifurcation, the bifurcation-based sensing methods yield significantly enhanced resolution and sensitivity compared to conventional, linear dynamics-based detection methods.…”

Section: Introductionmentioning

confidence: 99%

Predicting Non-Stationary and Stochastic Activation of Saddle-Node Bifurcation

Kim

Harne

Wang

2016

Journal of Computational and Nonlinear Dynamics

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Accurately predicting the onset of large behavioral deviations associated with saddle-node bifurcations is imperative in a broad range of sciences and for a wide variety of purposes, including ecological assessment, signal amplification, and microscale mass sensing. In many such practices, noise and non-stationarity are unavoidable and ever-present influences. As a result, it is critical to simultaneously account for these two factors toward the estimation of parameters that may induce sudden bifurcations. Here, a new analytical formulation is presented to accurately determine the probable time at which a system undergoes an escape event as governing parameters are swept toward a saddle-node bifurcation point in the presence of noise. The double-well Duffing oscillator serves as the archetype system of interest since it possesses a dynamic saddle-node bifurcation. The stochastic normal form of the saddle-node bifurcation is derived from the governing equation of this oscillator to formulate the probability distribution of escape events. Non-stationarity is accounted for using a time-dependent bifurcation parameter in the stochastic normal form. Then, the mean escape time is approximated from the probability density function (PDF) to yield a straightforward means to estimate the point of bifurcation. Experiments conducted using a double-well Duffing analog circuit verifies that the analytical approximations provide faithful estimation of the critical parameters that lead to the non-stationary and noise-activated saddle-node bifurcation.

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Binary MEMS gas sensors

Cited by 32 publications

References 23 publications

A Tunable Electrostatic MEMS Pressure Switch

A Tunable Electrostatic MEMS Pressure Switch

Designing Polymeric Sensing Materials for Analyte Detection and Related Mechanisms

Predicting Non-Stationary and Stochastic Activation of Saddle-Node Bifurcation

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