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A Multimode Index Detecting Sensor For Use In Plastic Concrete, Qiyu Chen
A Multimode Index Detecting Sensor For Use In Plastic Concrete, Qiyu Chen
Theses
This thesis describes a microcomputer-based measuring system using a laser diode source, a fiber optic sensor and a microcomputer DMA interface to test and analyze the entrained percentage of air in concrete.
The principle of refraction and reflection of light in optical fibers is applied to detection of air bubbles. Reflected light intensity signals are detected and transferred through a DMA interface to a laptop computer. Analysis of reflected light intensity produces a measurement of the air content of fresh concrete. Accuracy of the system is evaluated through extensive laboratory and field trials.