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Maintaining Transparency of a Heated MEMS Membrane for Enabling Long-Term Optical Measurements on Soot-Containing Exhaust Gas

Ensuring optical transparency over a wide spectral range of a window with a view into the tailpipe of the combustion engine, while it is exposed to the harsh environment of soot-containing exhaust gas, is an essential pre-requisite for introducing optical techniques for long-term monitoring of autom...

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Autores principales: Middelburg, Luke M., Ghaderi, Mohammadamir, Bilby, David, Visser, Jaco H., Zhang, Guo Qi, Lundgren, Per, Enoksson, Peter, Wolffenbuttel, Reinoud F.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6982716/
https://www.ncbi.nlm.nih.gov/pubmed/31861255
http://dx.doi.org/10.3390/s20010003
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author Middelburg, Luke M.
Ghaderi, Mohammadamir
Bilby, David
Visser, Jaco H.
Zhang, Guo Qi
Lundgren, Per
Enoksson, Peter
Wolffenbuttel, Reinoud F.
author_facet Middelburg, Luke M.
Ghaderi, Mohammadamir
Bilby, David
Visser, Jaco H.
Zhang, Guo Qi
Lundgren, Per
Enoksson, Peter
Wolffenbuttel, Reinoud F.
author_sort Middelburg, Luke M.
collection PubMed
description Ensuring optical transparency over a wide spectral range of a window with a view into the tailpipe of the combustion engine, while it is exposed to the harsh environment of soot-containing exhaust gas, is an essential pre-requisite for introducing optical techniques for long-term monitoring of automotive emissions. Therefore, a regenerable window composed of an optically transparent polysilicon-carbide membrane with a diameter ranging from 100 µm up to 2000 µm has been fabricated in microelectromechanical systems (MEMS) technology. In the first operating mode, window transparency is periodically restored by pulsed heating of the membrane using an integrated resistor for heating to temperatures that result in oxidation of deposited soot (600–700 °C). In the second mode, the membrane is kept transparent by repelling soot particles using thermophoresis. The same integrated resistor is used to yield a temperature gradient by continuous moderate-temperature heating. Realized devices have been subjected to laboratory soot exposure experiments. Membrane temperatures exceeding 500 °C have been achieved without damage to the membrane. Moreover, heating of membranes to ΔT = 40 °C above gas temperature provides sufficient thermophoretic repulsion to prevent particle deposition and maintain transparency at high soot exposure, while non-heated identical membranes on the same die and at the same exposure are heavily contaminated.
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spelling pubmed-69827162020-02-28 Maintaining Transparency of a Heated MEMS Membrane for Enabling Long-Term Optical Measurements on Soot-Containing Exhaust Gas Middelburg, Luke M. Ghaderi, Mohammadamir Bilby, David Visser, Jaco H. Zhang, Guo Qi Lundgren, Per Enoksson, Peter Wolffenbuttel, Reinoud F. Sensors (Basel) Article Ensuring optical transparency over a wide spectral range of a window with a view into the tailpipe of the combustion engine, while it is exposed to the harsh environment of soot-containing exhaust gas, is an essential pre-requisite for introducing optical techniques for long-term monitoring of automotive emissions. Therefore, a regenerable window composed of an optically transparent polysilicon-carbide membrane with a diameter ranging from 100 µm up to 2000 µm has been fabricated in microelectromechanical systems (MEMS) technology. In the first operating mode, window transparency is periodically restored by pulsed heating of the membrane using an integrated resistor for heating to temperatures that result in oxidation of deposited soot (600–700 °C). In the second mode, the membrane is kept transparent by repelling soot particles using thermophoresis. The same integrated resistor is used to yield a temperature gradient by continuous moderate-temperature heating. Realized devices have been subjected to laboratory soot exposure experiments. Membrane temperatures exceeding 500 °C have been achieved without damage to the membrane. Moreover, heating of membranes to ΔT = 40 °C above gas temperature provides sufficient thermophoretic repulsion to prevent particle deposition and maintain transparency at high soot exposure, while non-heated identical membranes on the same die and at the same exposure are heavily contaminated. MDPI 2019-12-18 /pmc/articles/PMC6982716/ /pubmed/31861255 http://dx.doi.org/10.3390/s20010003 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Middelburg, Luke M.
Ghaderi, Mohammadamir
Bilby, David
Visser, Jaco H.
Zhang, Guo Qi
Lundgren, Per
Enoksson, Peter
Wolffenbuttel, Reinoud F.
Maintaining Transparency of a Heated MEMS Membrane for Enabling Long-Term Optical Measurements on Soot-Containing Exhaust Gas
title Maintaining Transparency of a Heated MEMS Membrane for Enabling Long-Term Optical Measurements on Soot-Containing Exhaust Gas
title_full Maintaining Transparency of a Heated MEMS Membrane for Enabling Long-Term Optical Measurements on Soot-Containing Exhaust Gas
title_fullStr Maintaining Transparency of a Heated MEMS Membrane for Enabling Long-Term Optical Measurements on Soot-Containing Exhaust Gas
title_full_unstemmed Maintaining Transparency of a Heated MEMS Membrane for Enabling Long-Term Optical Measurements on Soot-Containing Exhaust Gas
title_short Maintaining Transparency of a Heated MEMS Membrane for Enabling Long-Term Optical Measurements on Soot-Containing Exhaust Gas
title_sort maintaining transparency of a heated mems membrane for enabling long-term optical measurements on soot-containing exhaust gas
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6982716/
https://www.ncbi.nlm.nih.gov/pubmed/31861255
http://dx.doi.org/10.3390/s20010003
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