Monitoring of mining induced subsidence through measurement of ground strains with Fiber Bragg Grating sensors
In this paper the application of Fiber Bragg Grating based sensors for the monitoring of mining induced subsidence phenomena is illustrated. A high number of sensors were installed in the pavement of a major highway thanks to the use of Bragg Grating arrays encapsulated in composite rods. The sensors and the associated demodulation equipment provide continuous measurements and allow the immediate implementation of safety measures by the authorities responsible for the highway.
Pultrusion of smart FRP composites
A laboratory scale pultrusion process has been developed to fabricate smart fiber reinforced plastic (FRP) materials. Microstructural analyses of the smart pultruded FRP was carried out using both an optical microscope and a Scanning Electron Microscope. The tensile properties and shear strength, i.e. modulus and strength, of pultruded carbon/vinylester and glass/vinylester rods were determined through mechanical testing. Testing was carried out on baseline pultruded samples, as well as those containing one and two embedded optical fibers. The pultruded carbon reinforced rods with and without optical fiber showed higher shear and tensile strength, as well as greater tensile modulus than did the glass fiber analogue. An embedded optical fiber did not have a significant effect upon the tensile properties of either glass or carbon pultruded FRP rod, but it slightly affected the shear strength of the glass fiber rods. Increased numbers of embedded optical fibers in the FRP rods had a more pronounced influence upon the shear strength. The interfaces between the resin matrix and the buffer coating on the optical fibers were examined and interpreted in terms of the coating's ability to resist high temperatures and its compatibility with resin matrix. Polyimide buffers proved to be superior to acrylate buffers.
The incidence of dead and dying fish in the Moray Firth, September 1963
Dead and dying fish were reported from the Moray Firth during a period of 15 days in September 1963. The initial mortalities were in the inner Firth, but they later spread outwards, especially eastwards along the southern shores of the Firth. Mass mortalities of the lugworm (Arenicola marina) also occurred in Scottish waters in 1962 and 1963, and at Balintorein Easter Ross fish and lugworm mortalities were contemporary.