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On-load tap changers (OLTCs) are electromechanical devices used in the voltage regulation of the electrical networks. A non-invasive monitoring method was developed using discrete wavelet transform (DWT) for condition assessment of on-load tap-changers using vibration analysis signals. The transient vibration signals emitted during a tap change are recorded and processed using spectral analysis and...
The purpose of this study is to present novel optical imaging techniques, based on all active Muller matrix optical polarimetric principles, for efficient detection, inspection and monitoring of semiconductor and microelectronic components, and spacecraft structure. The experimental results of this study indicate that the polarimetric imaging techniques are highly efficient in detecting defects on...
This paper describes the development of a monitoring and managing system for a PEM fuel-cell (FC) stack. This is a stand-alone unit that embodies two microcontrollers, hardware and sensing circuits, an LCD and a numeric pad. The proposed system acquires the most important gas parameters: mass flow rate, pressure and temperature. The output current and voltage are also acquired. The system design complies...
The waterjet (WJ) technology, whose characterization involves phenomena belonging to different fields of physics, presents some particular aspects which make it essential in some manufacturing operations where it is important to cut special or hard to machine materials by means of a cold process. In the present work, the correlations between the electric input signals, the mechanical and the fluid-dynamic...
Time domain reflectometry (TDR) technique is widely used in hydrology and soil science for accurate and flexible soil water content measurements. The most attractive advantages concerning the considered TDR measurement system are: good precision and accuracy, high reliability of the measuring head, a unique approach of pulsing a long coaxial probe and analysing the reflected voltage signature caused...
The paper is on the monitoring of optical telecommunication channels by means of specialized spectrophotometers, called optical performance monitors. An algorithm for data processing is proposed that makes possible the estimation of central wavelength, power and optical signal-to-noise ratio for all channels in parallel. It is demonstrated that it is guaranteeing an acceptable level of measurement...
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