Search

In this paper we propose low-cost solutions for sensitive optical liquid level monitoring, using standard polymer optical fibers (POF). Further we present a simple technique to reduce noise introduced by other light sources. The whole system can be integrated using six electronic components including a microcontroller. A simple circuit diagram is given. To determine the required dynamic range of the used analogto- digital converter, measurements have been performed. [ABSTRACT FROM AUTHOR]

Infusion monitoring is in great demand for the hospital. In this demo, we propose RF-iCare, an RFID-based approach for monitoring the infusion status, including the liquid level and the drop speed. With a tag array attached on the infusion bottle, we design an RSSI-based signal match model to estimate the liquid level. With a tag attached on the Murphy's dropper, we leverage the phase variation of the tag to estimate the drop speed. We implement RF-iCare with a COTS RFID system and evaluate it in the real-world hospitals. Our experiments demonstrate that RF-iCare can accurately monitor the completion of the infusion over 91% tests, and estimate the liquid level with the mean accuracy of 0.8 cm as well as the drop speed with the error rate less than 3%. [ABSTRACT FROM AUTHOR]

The paper presents a non-contact, non-destructive and at distance monitoring and diagnosis method for liquid tanks, in order to determine online the level of liquid in a tank. The method is based on the thermal inertia property of liquid and solid bodies and consists of taking thermographic images with a thermovision camera and processing them with specialized software. The authors' contribution consists of the chosen processing and analysis method and of the algorithm which leads to the online determination of the liquid level in the tank. The research results of the paper can be implemented in any domain in which the level of the liquid in a tank is difficult to be measured or determined through classic methods because of various reasons (toxic or difficult to access environments, etc). [ABSTRACT FROM AUTHOR]

In this paper we present a liquid level sensor based on multiple curves, U-shaped, using a single plastic optical fiber. In each of the curvatures of the fiber has a polished side of the region corresponding to the transition losses affecting the cladding and core of the fiber. This action increases the propagation loss but improves the sensitivity of the sensor. Using an 8 mm radius of curvature generated about 1dB loss in the fiber than 1 mm in diameter. With the polished side the transition region at an angle of inclination of 70 º to the axis of the fiber, corresponding to approximately the critical angle of the fiber, the losses increase by 0.1 dB when in contact with air and 0.4 dB when in contact with water. We present experimental results of 16 measurement points, each separated by 1.5 m, between air and water. [ABSTRACT FROM AUTHOR]

Analyzing low impedance liquids inside sealed containment vessels often presents a challenge. In some applications, wetted transducers or other invasive strategies are not permissible. Therefore, a strategy based on external clamp-on transducers has been investigated. Using pulse-echo measurements, the characteristics of multiple reflections from the liquid-vessel interface can be related to both liquid level and the liquid’s identity. The design challenges of a simple array setup for this approach have also been considered. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

In this paper a packaged sensor using fiber Bragg grating for under water level measurement is presented. The sensor is configured by fixing one end of a fiber Bragg grating with a diaphragm made up of polymer kept inside a hollow cylinder and the other end to the cylinder. As the level of water increases in the tank hydrostatic pressure at the bottom also increases. The diaphragm used in is to transfer this pressure to the axial strain on the grating. By utilizing the unique diaphragm-based grating packaging method, the level sensing range has been effectively enhanced. The results obtained indicate that this packaged sensor have long range, rugged and can be customized depending on the requirement. The sensitivity of the sensor is 6.057×10-6 per cm within the range 0 to 30 cm. [ABSTRACT FROM AUTHOR]

We have performed a Raman scattering study for single crystals of the rare-earth (RE) iron borates RFe3(BO3)4, R = Nd, Tb, Pr, in the range of temperatures 3-300 K. Electronic Raman scattering on the 4f levels of RE ions was registered, which enabled us to specify the schemes of crystal-field levels within ground multiplets of the RE ions. A splitting of the Kramers doublets in electronic Raman spectra of the neodymium iron borate testifies a magnetic ordering of the compound. Raman scattering from a coupled mode of the spin oscillations of the Fe and Nd subsystems was observed in NdFe3(BO3)4. [ABSTRACT FROM AUTHOR]