in this study, we have theoretically investigated designing possibility of a seismometer using fiber bragg grating (fbg) and metal bellows pairs attached on a mechanical system. this new seismometer can record earthquakes according to sensitivity of fiber optic to changes in physical parameters such as stress and strain. firstly, in order to understand the quantity and quality of sensor perform...

BACKGROUND Previous studies reported increased risk of cardiac events in subjects with fasting blood glucose (FBG) levels lower than the diagnostic threshold of diabetes mellitus. However, whether increased cardiac events in those with upper normal FBG is secondary to the shift of their cardiac sympathovagal balance towards sympathetic predominance is unknown. AIMS To assess the association b...

Introduction: Fibre Bragg gratings (FBGs) have proved themselves as the ideal candidates for measuring strain and temperature in smart structures, civil engineering or other harsh environments. The advantages of the FBG sensor over conventional electrical sensors include small size, light weight, immunity to electromagnetic interference, low cost and other inherent advantages of fibre-optic sen...

BACKGROUND Although diabetes is a well-known risk factor of atherosclerotic cardiovascular diseases, the cardiovascular disease risk of glycemia below the current diabetic threshold remains uncertain. METHODS AND RESULTS A total of 652,901 Korean men aged 30 to 64 years from the Korean National Health Insurance System were categorized into 8 groups by fasting blood glucose (FBG) level at base...

Surface temperature is an important parameter in clinical diagnosis, equipment state control, and environmental monitoring fields. The Fiber Bragg Grating (FBG) temperature sensor possesses numerous significant advantages over conventional electrical sensors, thus it is an ideal choice to achieve high-accuracy surface temperature measurements. However, the effects of the ambient temperature and...

Dissolved hydrogen is a symbol gas decomposed by power transformer oil for electrical faults such as overheat or partial discharges. A novel D-shaped fiber Bragg grating (D-FBG) sensor is herein proposed and was fabricated with magnetron sputtering to measure the dissolved hydrogen concentration in power transformer oil in this paper. Different from the RI (refractive index)-based effect, D-FBG...

The reflective characteristics of a multimode fiber Bragg grating (MM-FBG) and the changes of reflective spectra with mode excitation conditions in the multi-mode fiber were investigated. Two multiwavelength fiber laser configurations using offset launch technique to MM-FBG with hybrid gain mediums are proposed and demonstrated. Different multiwavelength outputs were obtained by variation of th...

Clamped fiber Bragg grating (FBG) sensors have been widely applied in engineering strain measurements due to their advantages of high flexibility and efficiency. However, due to the existence of the interlayer, the strain measured by the encapsulated FBG sensor is not equal to the strain of the host material, which causes strain measurement errors. In this paper, the strain transfer analysis of...

This paper presents the fabrication of chirped Fiber Bragg Grating (CFBG) from uniform Fiber Bragg Grating (FBG) by etching technique in order to utilize it as refractive index sensors. Etching is carried out with the presence of a layer of silicone oil on top of the hydrofluoric acid to achieve partial-etching of the FBGs. The partiallyetched FBGs exhibit two different modes: fundamental mode ...