The Experts below are selected from a list of 109311 Experts worldwide ranked by ideXlab platform
Gangbing Song - One of the best experts on this subject based on the ideXlab platform.
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monitoring concrete deterioration due to reinforcement corrosion by integrating acoustic emission and fbg strain Measurements
Sensors, 2017Co-Authors: Weijie Li, Changhang Xu, Siu Chun Michael Ho, Bo Wang, Gangbing SongAbstract:Corrosion of concrete reinforcement members has been recognized as a predominant structural deterioration mechanism for steel reinforced concrete structures. Many corrosion detection techniques have been developed for reinforced concrete structures, but a dependable one is more than desired. Acoustic emission technique and fiber optic sensing have emerged as new tools in the field of structural health monitoring. In this paper, we present the results of an experimental investigation on corrosion monitoring of a steel reinforced mortar block through combined acoustic emission and fiber Bragg grating strain Measurement. Constant current was applied to the mortar block in order to induce accelerated corrosion. The monitoring process has two aspects: corrosion initiation and crack propagation. Propagation of cracks can be captured through corresponding acoustic emission whereas the mortar expansion due to the generation of corrosion products will be monitored by fiber Bragg grating strain sensors. The results demonstrate that the acoustic emission sources comes from three different types, namely, evolution of hydrogen bubbles, generation of corrosion products and crack propagation. Their corresponding properties are also discussed. The results also show a good correlation between acoustic emission activity and expansive strain measured on the specimen surface.
Soren Knudsen Kaer - One of the best experts on this subject based on the ideXlab platform.
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estimation of membrane hydration status for standby proton exchange membrane fuel cell systems by complex impedance Measurement Constant temperature stack characterization
International Journal of Hydrogen Energy, 2013Co-Authors: Benoit Bidoggia, Soren Knudsen KaerAbstract:Abstract Fuel cell-based backup units are characterized by long standby periods but they must be ready to start at any instant in the shortest possible time. In the case of low temperature proton exchange membrane fuel cells, the estimation of the hydration status of the fuel cell's membrane during standby is important for determining the cell's ability to perform a fast and safe startup. In this article, non-conventional electrochemical impedance spectroscopy (EIS) is suggested as a method to estimate the membrane's hydration status. The proposed technique differs from standard EIS in that the current through the fuel cell cannot contain a DC component, since hydrogen is absent. A 56-cell fuel cell stack has been symmetrically fed with air, whose temperature and relative humidity were controlled, and its complex impedance was measured at different frequencies and for different values of relative humidity at Constant temperature. Power regression models were applied to the data, and the relationships between complex impedance and relative humidity were found. The results showed that the proposed technique is a viable way for estimating the membrane hydration status of a fuel cell stack during standby. Moreover, the most suitable frequency values at which the Measurements should be performed are given.
Weijie Li - One of the best experts on this subject based on the ideXlab platform.
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monitoring concrete deterioration due to reinforcement corrosion by integrating acoustic emission and fbg strain Measurements
Sensors, 2017Co-Authors: Weijie Li, Changhang Xu, Siu Chun Michael Ho, Bo Wang, Gangbing SongAbstract:Corrosion of concrete reinforcement members has been recognized as a predominant structural deterioration mechanism for steel reinforced concrete structures. Many corrosion detection techniques have been developed for reinforced concrete structures, but a dependable one is more than desired. Acoustic emission technique and fiber optic sensing have emerged as new tools in the field of structural health monitoring. In this paper, we present the results of an experimental investigation on corrosion monitoring of a steel reinforced mortar block through combined acoustic emission and fiber Bragg grating strain Measurement. Constant current was applied to the mortar block in order to induce accelerated corrosion. The monitoring process has two aspects: corrosion initiation and crack propagation. Propagation of cracks can be captured through corresponding acoustic emission whereas the mortar expansion due to the generation of corrosion products will be monitored by fiber Bragg grating strain sensors. The results demonstrate that the acoustic emission sources comes from three different types, namely, evolution of hydrogen bubbles, generation of corrosion products and crack propagation. Their corresponding properties are also discussed. The results also show a good correlation between acoustic emission activity and expansive strain measured on the specimen surface.
Benoit Bidoggia - One of the best experts on this subject based on the ideXlab platform.
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estimation of membrane hydration status for standby proton exchange membrane fuel cell systems by complex impedance Measurement Constant temperature stack characterization
International Journal of Hydrogen Energy, 2013Co-Authors: Benoit Bidoggia, Soren Knudsen KaerAbstract:Abstract Fuel cell-based backup units are characterized by long standby periods but they must be ready to start at any instant in the shortest possible time. In the case of low temperature proton exchange membrane fuel cells, the estimation of the hydration status of the fuel cell's membrane during standby is important for determining the cell's ability to perform a fast and safe startup. In this article, non-conventional electrochemical impedance spectroscopy (EIS) is suggested as a method to estimate the membrane's hydration status. The proposed technique differs from standard EIS in that the current through the fuel cell cannot contain a DC component, since hydrogen is absent. A 56-cell fuel cell stack has been symmetrically fed with air, whose temperature and relative humidity were controlled, and its complex impedance was measured at different frequencies and for different values of relative humidity at Constant temperature. Power regression models were applied to the data, and the relationships between complex impedance and relative humidity were found. The results showed that the proposed technique is a viable way for estimating the membrane hydration status of a fuel cell stack during standby. Moreover, the most suitable frequency values at which the Measurements should be performed are given.
Bo Wang - One of the best experts on this subject based on the ideXlab platform.
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monitoring concrete deterioration due to reinforcement corrosion by integrating acoustic emission and fbg strain Measurements
Sensors, 2017Co-Authors: Weijie Li, Changhang Xu, Siu Chun Michael Ho, Bo Wang, Gangbing SongAbstract:Corrosion of concrete reinforcement members has been recognized as a predominant structural deterioration mechanism for steel reinforced concrete structures. Many corrosion detection techniques have been developed for reinforced concrete structures, but a dependable one is more than desired. Acoustic emission technique and fiber optic sensing have emerged as new tools in the field of structural health monitoring. In this paper, we present the results of an experimental investigation on corrosion monitoring of a steel reinforced mortar block through combined acoustic emission and fiber Bragg grating strain Measurement. Constant current was applied to the mortar block in order to induce accelerated corrosion. The monitoring process has two aspects: corrosion initiation and crack propagation. Propagation of cracks can be captured through corresponding acoustic emission whereas the mortar expansion due to the generation of corrosion products will be monitored by fiber Bragg grating strain sensors. The results demonstrate that the acoustic emission sources comes from three different types, namely, evolution of hydrogen bubbles, generation of corrosion products and crack propagation. Their corresponding properties are also discussed. The results also show a good correlation between acoustic emission activity and expansive strain measured on the specimen surface.