ABSTRACT
We demonstrate diagnosis of several machine-condition failures using wide-frequency-band interrogation of fiber Bragg grating (FBG) sensors. In collaboration with Israel's national water company Mekorot Ltd., a scaled-down version of a semi-submerged pumping system was constructed. By monitoring broadband signals from DC to ultrasound (>M H z), at different points of the engine and the submersed pump, the system was able to diagnose incipient cavitation, faulty bearings, and submerged dynamic water-level measurements. In addition, a metal embedded FBG sensor was investigated, revealing the potential of using FBGs in applications where bonding is problematic such as bearing housing. These results prove that wideband data acquisition, together with advanced analytics, could open a variety of new applications in the fields of structural health and machine-condition monitoring.
ABSTRACT
Here we report an electrochemical immunoassay platform called Proton-ELISA (H-ELISA) for the detection of bioanalytes. H-ELISA uniquely utilizes protons as an immunoassay detection medium, generated by the enzyme glucose oxidase (GOx) coupled with Fenton's reagent in a proton amplification reaction cascade that results in a highly amplified signal. A proton-sensitive dual-gated ion-sensitive field effect transistor (DG-ISFET) sensor was also developed for sensitive and accurate detection of the proton signal in H-ELISA. The DG-ISFET sensor comprises of a 128â¯×â¯128 array of 16,384 sensing transistors each with an individually addressable back gate to allow for a very high signal throughput and improved accuracy. We then demonstrated that the platform could detect C-reactive protein and immunoglobulin E down to concentrations of 12.5 and 125â¯pg/mL, respectively. We further showed that the platform is compatible with complex biological sample conditions such as human serum, suggesting that the platform is sufficiently robust for potential diagnostic applications.
