A novel half-bonded chirped fibre Bragg grating (CFBG) on a natural rubber diaphragm has been proposed to enhance the sensitivity and to compensate the temperature effects of a hydrostatic liquid level sensor. This innovative fabrication method resulted in the narrowing of the bandwidth with the hydrostatic pressure sensitivity recorded at -253 pm/kPa and water column sensitivity at -0.0253 nm/cm. The bandwidth modulation measurement was insensitive to temperature variations, when compared to centre wavelength modulation measurement. Furthermore, the proposed hydrostatic liquid level sensor is compatible with low cost photodetector.

This paper investigates impact of magnetite dispersed in butanol and added to two varied blends of palm biodiesel and diesel (B20 and B30). The developed fuel samples were characterized and tested on single cylinder diesel Yanmar engine (L70N) to observe engine behavior for emissions and performance. Results are compared with two reference fuels: YF50 fuel contains 50 ppm magnetite in B20 and B_n10Y90 contains 10% butanol with 90% B20. Addition of magnetite and butanol depletes emissions levels and improve performance compared to ordinary B20 and B30 however; samples with higher dosage of magnetite (150 ppm) yielded better results in performance and emission compared with lower dosage (75 ppm). The best sample was C10Z90 which entails 150 ppm magnetite in butanol added at 10% to B30. Brake thermal efficiency (BTE) at highest brake power (BP) point for C10Z90 was 37.28% compared to others (32.88%, 35.22% and 35.96%). Additionally, brake specific fuel consumption (BSFC) of C10Z90 was at least 8.29 g/Kw.hr and at most 84.52 g/Kw.hr less than other samples at highest BP point. Results indicated C10Z90 was lower in carbon-monoxide, hydrocarbon and smoke except for oxides of nitrogen. Artificial Neural Network (ANN) model successfully predicted BTE, BSFC and emissions of the dual fuel application.

The use of FBG sensors in water level monitoring has shown great advantages over the use of conventional electrical sensors. However, much effort is still required to increase their sensitivity towards water level measurement with eliminated sensitivity towards temperature. Here, the FBG was bonded on a PVC polymer plastic cantilever beam and rubber diaphragm structure. The sensing mechanism was based on the differential FBG method. Variations of the water level from 0 to 100 cm obtained the sensitivity of 0.0639 nm/cm with the linearity of 98.06%. The poor linearity was mainly due to the manual fabrication errors. However, this uncertainty can be overcome through the polynomial regression fit in determining the water level measurement. The measured water level was closed to the actual water level at a tolerance of ±2 cm. For temperature effects, the sensitivity was inconspicuous, recorded at only 0.0003 nm/°C across the range of 10 °C to 60 °C.

A highly sensitive fibre Bragg grating (FBG) geophone with temperature insensitivity has been developed for low-frequency seismic detection. This geophone utilizes a rubber-based diaphragm combined with a differential FBG technique to enhance vibrational sensitivity and eliminate temperature effects. This innovative method achieves a high vibrational sensitivity of 169.71 pm/g across a frequency range of 1 to 36 Hz while a low temperature sensitivity of 1.21 pm/°C is obtained over the range of 10 °C to 40 °C. Frequency spectrum comparisons demonstrate that the FBG geophone performs comparably to conventional electrical geophones.