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Fiber Optical Micro-Detectors for Oxygen Sensing in Power Plants Progress Report

Description: A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Alkali salts of Mo{sub 6}Cl{sub 12} were synthesized and heated to 280 C for one hour in air. Optical measurements of the thermally treated material confirm the potential of the salts as lumophores in high temperature fiber optic sensors. In additi… more
Date: July 1, 2004
Creator: Baker, Gregory L.; Ghosh, Ruby N. & III, D.J. Osborn
Partner: UNT Libraries Government Documents Department
open access

SILICON CARBIDE MICRO-DEVICES FOR COMBUSTION GAS SENSING UNDER HARSH CONDITIONS

Description: A sensor based on the wide bandgap semiconductor, silicon carbide (SiC), has been developed for the detection of combustion products in power plant environments. The sensor is a catalytic gate field effect device that can detect hydrogen containing species in chemically reactive, high temperature environments. Robust metallization and electrical contacting techniques have been developed for device operation at elevated temperatures. To characterize the time response of the sensor responses in t… more
Date: April 1, 2004
Creator: Ghosh, Ruby N.; Tobias, Peter & Tobin, Roger G.
Partner: UNT Libraries Government Documents Department
open access

Phylogenetic & Physiological Profiling of Microbial Communities of Contaminated Soils/Sediments: Identifying Microbial consortia...

Description: The goals of this study were: (1) survey the microbial community in soil samples from a site contaminated with heavy metals using new rapid molecular techniques that are culture-independent; (2) identify phylogenetic signatures of microbial populations that correlate with metal ion contamination; and (3) cultivate these diagnostic strains using traditional as well as novel cultivation techniques in order to identify organisms that may be of value in site evaluation/management or bioremediation.
Date: May 26, 2004
Creator: Marsh, Terence L.
Partner: UNT Libraries Government Documents Department
open access

Fiber Optical Micro-Detectors for Oxygen Sensing in Power Plants Progress Report

Description: A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. One of the critical materials issues is to demonstrate that the luminescent cluster immobilized in the sol-gel porous support can withstand high temperature. At the same time the sol-gel matrix must have a high permeability to oxygen. Using a potas… more
Date: April 1, 2005
Creator: Baker, Gregory L.; Ghosh, Ruby N.; III, D.J. Osborn & Zhang, Po
Partner: UNT Libraries Government Documents Department
open access

Fiber Optical Micro-Detectors for Oxygen Sensing in Power Plants Progress Report

Description: A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. High temperature measurements of the emission of clusters in sol gel films show that the luminescence intensity from the films follow a 1/T relationship from room temperature to 150 C, and then declines at a slower rate at higher temperatures. The … more
Date: October 1, 2004
Creator: Baker, Gregory L.; Ghosh, Ruby N. & III, D.J. Osborn
Partner: UNT Libraries Government Documents Department
open access

DEVELOPMENT OF SiC DEVICES FOR DIAGNOSTICS AND CONTROL OF COMBUSTION PRODUCTS IN ENERGY PLANT ENVIRONMENTS

Description: A sensor based on the wide bandgap semiconductor, silicon carbide (SiC), has been developed for the detection of combustion products in power plant environments. The sensor is a catalytic gate field effect device that can detect hydrogen containing species in chemically reactive, high temperature environments. The response of these metal/insulator/SiC (MISiC) devices to reducing gases has been assumed to be due to the reduction in the metal work function at the metal/oxide interface that shifts… more
Date: December 1, 2003
Creator: Ghosh, Ruby N. & Tobias, Peter
Partner: UNT Libraries Government Documents Department
open access

Fiber Optical Micro-Detectors for Oxygen Sensing in Power Plants Progress Report

Description: A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. One of the critical materials issues is to demonstrate that the luminescent cluster immobilized in the sol-gel porous support can withstand high temperature. At the same time the sol-gel matrix must have a high permeability to oxygen. Using a potas… more
Date: January 1, 2005
Creator: Baker, Gregory L.; Ghosh, Ruby N.; III, D.J. Osborn & Zhang, Po
Partner: UNT Libraries Government Documents Department
open access

Fiber Optical Micro-Detectors for Oxygen Sensing in Power Plants Progress Report

Description: 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{sub 6}Cl{sub 12} clusters [2,3], so … more
Date: January 1, 2003
Creator: Baker, Gregory L.; Ghosh, Ruby N. & III, D.J. Osborn
Partner: UNT Libraries Government Documents Department
open access

Fiber Optical Micro-Detectors for Oxygen Sensing in Power Plants Progress Report

Description: Mo{sub 6}Cl{sub 12}, a cluster compound whose luminescence depends on the ambient concentration of oxygen, is the basis for a real-time oxygen sensor for combustion applications. Previously, the properties of Mo{sub 6}Cl{sub 12} have largely been studied at room temperature; these studies have now been extended to 200 C. Optical microscopy shows that Mo{sub 6}Cl{sub 12} undergoes a steady change in color as it is heated from room temperature to 200 C, changing from canary yellow to crimson and … more
Date: July 1, 2003
Creator: Baker, Gregory L.; Ghosh, Ruby N. & III, D.J. Osborn
Partner: UNT Libraries Government Documents Department
open access

4th International Plant Biomechanics Conference Proceedings (Abstracts)

Description: The 4th International Plant Biomechanics Conference facilitated an interdisciplinary exchange between scientists, engineers, and educators addressing the major questions encountered in the field of Plant Biomechanics. Subjects covered by the conference include: Evolution; Ecology; Mechanoreception; Cell Walls; Genetic Modification; Applied Biomechanics of Whole Plants, Plant Products, Fibers & Composites; Fluid Dynamics; Wood & Trees; Fracture Mechanics; Xylem Pressure & Water Transport; Modeli… more
Date: July 20, 2003
Creator: Telewski, Frank W.; Koehler, Lothar H. & Ewers, Frank W.
Partner: UNT Libraries Government Documents Department
open access

SILICON CARBIDE MICRO-DEVICES FOR COMBUSTION GAS SENSING UNDER HARSH CONDITIONS

Description: A sensor based on the wide bandgap semiconductor, silicon carbide (SiC), has been developed for the detection of combustion products in power plant environments. The sensor is a catalytic gate field effect device that can detect hydrogen containing species in chemically reactive, high temperature environments. For these capacitive sensors we have determined that the optimum sensor operating point in terms of sensor lifetime and response time is at midgap. Detailed measurements of the oxide leak… more
Date: October 1, 2004
Creator: Ghosh, Ruby N.; Tobias, Peter & Tobin, Roger G.
Partner: UNT Libraries Government Documents Department
open access

Fiber Optical Micro-Detectors for Oxygen Sensing in Power Plants Progress Report

Description: A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. The luminescence of Mo{sub 6}Cl{sub 12} immobilized in a sol-gel matrix was measured as a function of heater temperature up to 200 C, in an inert environment. While the luminescence decreased with temperature, the integrated intensity at 200 C shou… more
Date: April 1, 2004
Creator: Baker, Gregory L.; Ghosh, Ruby N. & III, D.J. Osborn
Partner: UNT Libraries Government Documents Department
open access

Fiber Optical Micro-Detectors for Oxygen Sensing in Power Plants Progress Report

Description: More Mo{sub 6}Cl{sub 12} has been synthesized. We have found that previous ambiguous x-ray powder diffraction results are due to disruption of long-range order in the crystals during the heating stage of the synthesis. The quartz cell heaters have been redesigned and are able to heat the substrate. Initial films have been fabricated and are currently under investigation to determine optimal deposition conditions.
Date: May 1, 2003
Creator: Baker, Gregory L.; Ghosh, Ruby N. & III, D.J. Osborn
Partner: UNT Libraries Government Documents Department
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