Demonstration of a high-temperature fiber-optic gas sensor made with a sol-gel process to incorporate a fluorescent indicator

Remillard, J. T.; Jones, Jeffrey R.; Poindexter, B. D.; Narula, Chaitanya K.; Weber, W. H.

doi:10.1364/ao.38.005306

Cited by 27 publications

(28 citation statements)

References 13 publications

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“…Remillard and coworkers have shown that a sol gel supported copper based oxygen sensor can be used in a combustion process. [6] With these facts in hand, we anticipate promising results from our design.…”

Section: Introductionmentioning

confidence: 88%

“…To improve the long-term stability at 200 °C, sensors were prepared by coating optical fibers with 50 and 60 w/w% blends resulting in a more uniform coating, enhanced oxygen quenching, and improved adhesion. Our 3 rd quarter milestone was to: "Complete immobilization of alkali metal salt derivatives of Mo 6 Cl 12 at the tip of a high temperature silica optical fiber.…”

Section: Executive Summarymentioning

confidence: 99%

“…Following the procedure described by Remillard et al, [6] a pulverized composite 31 / solgel solution blend was placed into a 20 mL vial and attached to a Paasche double-action internal-mix airbrush. A single coat was applied to a 2.4 cm × 1.25 cm quartz slide for 1 second at a distance of 4 cm from the airbrush tip using nitrogen gas at 10 psi.…”

Section: Dip Coatingmentioning

confidence: 99%

“…This requires the ability to sense oxygen levels over a broad range of concentrations with fast response times. Mussell, Newsham, and Ruud previously reported preliminary studies of the synthesis and optical properties of Mo 6 Cl 12 -based clusters relevant to this project. [1][2][3][4] Mussell described the synthesis of the molybdenum clusters, and Newsham gives a good account of the properties of neutral Mo 6 Cl 12 clusters and their salts, in both solution and a sol gel matrix.…”

Section: Introductionmentioning

confidence: 99%

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Fiber Optical Micro-Detectors for Oxygen Sensing in Power Plants

Baker¹,

Ghosh²,

Osborn³

et al. 2005

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A reflection mode fiber optic oxygen sensor is being developed that can operate at high temperatures for power plant applications. The sensor is based on the 3 O 2 quenching of the red emission from hexanuclear molybdenum chloride clusters. Two critical materials issues are the cluster's ability to withstand high temperatures when immobilized in a porous the sol-gel support, and whether after heating to high temperatures, the sol-gel matrix maintains a high and constant permeability to oxygen to support rapid quenching of luminescence. We used a composite materials approach to prepare stable sensing layers on optical fibers. We dispersed 60 w/w% of a pre-cured sol-gel composite containing the potassium salt of molybdenum clusters (K 2 Mo 6 Cl 14 ) into a sol-gel binder solution, and established the conditions necessary for deposition of sol-gel films on optical fibers and planar substrates. The fiber sensor has an output signal of 5 nW when pumped with an inexpensive commercial 365 nm ultraviolet light emitting diode (LED). Quenching of the sensor signal by oxygen was observed up to a gas temperature of 175 °C with no degradation of the oxygen permeability of the composite after high temperature cycling. On planar substrates the cluster containing composite responds within <1 second to a gas exchange from nitrogen to oxygen, indicating the feasibility of real-time oxygen detection. (10×) showing a sol-gel monolith containing MM5 pulverized using a mortar and pestle, 25 -250 µm particle size, (b) a sol-gel monolith (no clusters), 1 -2 µm particle size, and (c) dark field image (100×) showing a sol-gel monolith containing MM5 pulverized via ball milling, 2 -8 µm particle size. 3 20Figure 8 Typical dip coating results for deposition of composite / sol-gel binder blends 1000 µm diameter fibers. Details of the fiber fabrication and resultant measurements are in Table 2. 21Figure 9: Processing schemes used for fibers and planar sample (slide) 38Q. The principal differences between 38Q and the fibers is that (i) the binder used for 38Q contained molybdenum clusters whereas that for the fibers did not and (ii) 38Q was cured at 200 °C whereas the fibers were cured at 70 °C.The same cluster/sol-gel monolith was used for all samples. 22Figure 10: Specifications of the optical fibers used for oxygen fiber sensor fabrication and for testing the mechanical properties of the sol-gel film. Figure 13: High temperature fiber sensor luminescence and oxygen quenching for Fiber D (see Figure 12 for details). Here we demonstrate oxygen quenching of 1.3 ± 0.2 at 175 °C. 28Figure14: Thermal dependence of the emission spectra for film 38Q cured at 200 C for 30 minutes. The emission intensity is a function of temperature, but the line-shape is temperature independent. All spectra were sampled in 99.999% nitrogen environments. The cluster source was MM8 and the film concentration is (5±1.1) × 10 20 clusters/cm 3 based on an estimated film thickness of (700 ± 300) nm. The result demonstration that room temperature quenching ratio...

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Section: Introductionmentioning

confidence: 88%

Section: Executive Summarymentioning

confidence: 99%

Section: Dip Coatingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Fiber Optical Micro-Detectors for Oxygen Sensing in Power Plants

Baker¹,

Ghosh²,

Osborn³

et al. 2005

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“…Remillard and coworkers have shown that the typical dip-coating technique produced non-uniform silica sol beads on the end of an optical fiber [5]. They devised an interesting approach for applying a sol-gel / fluorophore slurry to the end of an optical fiber.…”

Section: Executive Summarymentioning

confidence: 99%

Fiber Optical Micro-Detectors for Oxygen Sensing in Power Plants

Baker¹,

Ghosh²,

Osborn³

2003

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In this report, initial results pertaining to the synthesis molybdenum clusters and characterization using absorption, optical microscopy, and x-ray powder diffraction are discussed. The synthesis was performed according to literature [1], but results from x-ray powder diffraction indicate that the synthesis did not give the desired compound. The absorption and optical microscopy indicate that the compound synthesized has properties similar to the desired Mo 6 Cl 12 clusters [2,3], so it is unclear as of yet what happened. The sample cell for performing high temperature spectroscopy on thin films of the molybdenum clusters at elevated temperature in a controlled gas environment was designed and an initial prototype was built.

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A Critical Overview of Sensors for Monitoring Polymerizations

Fonseca

Dubé

Penlidis

2009

Macro Reaction Engineering

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The available on‐line and in‐line sensor technologies developed for polymerization reactors from 1990 until today are discussed and critically reviewed. About 600 references are included, which evidence the growth in sensor technology in the last two decades. Sensors for operational parameters in polymer reactors (i.e. temperature, pressure, level and flow) as well as sensors for polymer property monitoring (i.e. calorimetry, chromatography and spectroscopy, among others) are included. Complementary topics such as state estimation, multivariate statistical methods, fault diagnosis techniques and optimal sensor selection and location are briefly covered.

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Demonstration of a high-temperature fiber-optic gas sensor made with a sol-gel process to incorporate a fluorescent indicator

Cited by 27 publications

References 13 publications

Fiber Optical Micro-Detectors for Oxygen Sensing in Power Plants

Fiber Optical Micro-Detectors for Oxygen Sensing in Power Plants

Fiber Optical Micro-Detectors for Oxygen Sensing in Power Plants

A Critical Overview of Sensors for Monitoring Polymerizations

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