Escherichia coli (E. coli) is a large and diverse bacteria group that inhabits the intestinal tract of many mammals. Most E. coli strains are harmless, however some of them are pathogenic, meaning they can make one sick if ingested. By being in the feces of animals and humans, its presence in water and food is used as indicator of fecal contamination. The main method for this microorganism detection is the bacterial culture medium that is time-consuming and requires a laboratory with specialized personnel. Other sophisticated methods are still not fast enough because they require sending samples to a laboratory and with a high cost of analysis. In this paper, a gold-coated U-shaped plastic optical fiber (POF) biosensor for E. coli bacteria detection is presented. The biosensor works by intensity modulation principle excited by monochromatic light where the power absorption is imposed by predominant effect of either bending loss or surface plasmon resonance (SPR), depending on the gold thickness. Bacterial selectivity is obtained by antibody immobilization on the fiber surface. The biosensor showed a detection limit of 1.5 × 10³ colony-forming units (CFU)/mL, demonstrating that the technology can be a portable, fast response and low-cost alternative to conventional methodologies for quality analysis of water and food.

A flare system in oil platform is a combustion stack used to burn off excess gases that cannot be processed and gases that have to be eliminated in emergency shutdown to avoid the risk of explosion. Gas flow measurement in flares is still considered challenging because the measurement has to attend many specific demands, quite different from any other flow measurement application. For these types of measurements many sensor technologies are available, however they are all very expensive, and only a few ones can attend all demands. The objective of this paper is to present a flow rate sensor based on Fiber Bragg Grating (FBG), cross-correlation and heatwave travel time techniques. The system was developed with inexpensive components and is little-intrusive, capable of attaining the rangeability of the flare demand and independent of gas composition, pressure and temperature.