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Pawel Dworak, Krzysztof Jaroszewski
RECONFIGURATION OF A DYNAMICALLY DECOUPLED SYSTEM AFTER ACTUATOR FAULT

In the paper problems with reconfiguration of a dynamically decoupled system after actuator fault are considered. On the basis of a universal algorithm for synthesis of control system for proper, square, right and left-invertible multi-input multi-output LTI dynamic (MIMO) plants necessary calculations after fault occurs are discussed. It is presented a reconfiguration algorithm defining all calculations that need to be done to adapt decoupler to new working conditions ensuring stability and physical reliability of all parts of the system.

Marcantonio Catelani, Lorenzo Ciani, Enrico Simoni
PHOTOVOLTAIC INVERTER: THERMAL CHARACTERIZATION TO IDENTIFY CRITICAL COMPONENTS

The renewable energy industry has been growing remarkably over the last years and the recent Fukushima nuclear crisis has given a further incentive worldwide. In this context, solar radiation represents one of the most accessible and clean energy resources thus the number and scale of photovoltaic (PV) systems installed grows, so does the size of the associated investments, and the related opportunities and risks. It therefore becomes increasingly important for developers and investors the assessment of the quality, reliability and electrical performances of their PV plants. PV systems are highly reliable, but like any complex system, they may fail. Neglecting the effects of those failures may lead to unreasonably optimistic performance and life cycle cost predictions.
In this paper a study of the thermal characterization of a PV inverter is proposed in order to individuate its critical components. The final aim is a proposal of a reliable design solution considering the real condition of use for the plant and, consequently, an improvement of the PV inverter yield. At the same time, the study allows to optimize both the availability and the maintainability of the inverter hence of the whole PV plant.

L. Fabbiano, G. Vacca
A NOVEL ALGORITHM FOR THE AUTHENTICATION OF INDIVIDUALS THROUGH RETINAL VASCULAR PATTERN RECOGNITION

This paper describes an original numerical procedure for the recognition of images applied to the case of individuals’ authentication by using biometric pattern, like the retinal vascular one. Because of the statistical nature of the recognition procedure, the 2x2 confusion matrix, typical of decision tests for binary classification models, is here considered in order to evaluate the performances of the proposed matching algorithm. An ad hoc procedure is then performed both to build the templates of reference database and to evaluate the threshold for the final decision test.

Marcantonio Catelani, Lorenzo Ciani, Giovanni Barile
DESIGN AND RELIABILITY ASSESSMENT OF AN AVIONICS TFT-LCD DISPLAY

In avionics application it’s fundamental that each system, sub-system or a component achieves a high level of reliability. To this aim, reliability prediction and an accurate test planning are required in the design phase in order to avoid undesirable fault or failure during the operating life cycle of any aeronautics equipment. In this paper, a research activity concerning the design and reliability assessment of TFT-LCD for avionics application are presented. The results obtained by the development, characterization and reliability analysis of a customize display which will be installed in a military aircraft cockpit are discussed. Being the device under test an innovative display, it’s fundamental an evaluation and analysis of the reliability performances. Then some test on the display has been performed to validate the customizing process.

Marcantonio Catelani, Lorenzo Ciani, Valentina Luongo
FUNCTIONAL SAFETY ASSESSMENT: AN ISSUE FOR TECHNICAL DIAGNOSTICS

The paper discusses a case study concerning the functional safety assessment based on the evaluation of the Safe Failure Fraction (SFF) for a complex system. Being such evaluation made according to IEC61508 standard, the paper focused on some related ambiguities. The paper is structured in two phases. First, a reliability prediction of each component of the system is implemented and then a Failure Mode and Effect, Diagnostic Analysis (FMEDA) is applied, in order to collect information about failure condition of each component. By using this approach it is possible to study SFF of different complex systems in compliance with qualitative requirements described in the aforementioned standard.

O.Yu. Bushuev, A.S. Semenov, A.O. Chernavskiy, A.L. Shestakov
DETECTING CHANGES IN THE CONDITION OF A PRESSURE TRANSDUCER BY ANALYSING ITS OUTPUT SIGNAL

A technique of detecting changes in the condition of a pressure transducer is described. The method is based on a spectral analysis of transducer output signal and estimating its frequency response. The study of the transducer finite-element model and experimental results show that it is possible to detect faults by this way so this technique can be used to develop a self-validating pressure sensor.

Miroslav Uher, Petr Benes
MEASUREMENT OF PARTICLE SIZE DISTRIBUTION BY ACOUSTIC EMISSION METHOD

Continuous measurement of size distribution of particles is the necessary parameter regarding the control of some specific production processes. A possible solution is the use of the acoustic emission method which is based on the measurement and analysis of pressure pulses generated by an impact of solid particles against a solid obstacle. Our paper focuses on the practical verification of the method in laboratory conditions. Two sets of experiments were conducted with air-borne particles. Based on the completed experiments it can be concluded that it is possible to establish the proportion of solid particle fractions using the acoustic emission method.

Yu. Mikhailova, I. D. Welt
SIMULATION OF THE ELECTROMAGNETIC FLOWMETERS

The electromagnetic flowmeters allow the discharge measurement under intricate flow structures in form of: inexact channel filling with measured medium; nonuniform allocation of a phase composition under coal, sand pulp and suspension measurements; change of velocity allocation by channel section with the close locating fixings of tubing; and etc. There is necessary the specialized metrological equipment under the circumstances for electromagnetic flowmeter checking. It is possible to make the calibration of electromagnetic flowmeters under intricate flow shapes by means of simulation method.

Rongmo Luo, Jian Wu, Steven Wan
NUMERICAL STUDY ON THE EFFECT OF LOW REYNOLDS NUMBER FLOWS IN STRAIGHT TUBE CORIOLIS FLOWMETERS

A numerical model has been developed to simulate the single straight tube Coriolis mass flowmeters (CMFs), to study the vibration mode shape of the sensor tube for mass flow rate measurement. In this model, a finite volume (FV) code for fluid flow analysis and a finite element (FE) code for structural analysis are coupled based on the theories of fluid-structure interaction. The effect of the low Reynolds number on the sensitivity of CMF has been studied in details, and the simulation results can gain a deeper understanding of the error behaviour of CMFs under high viscous flow.

A. Hribernik, M. Fike, G. Bombek, M. Hribersek
EXPERIMENTAL INVESTIGATION OF AN UNSTEADY FLOW FIELD AROUND AN AIRFOIL

A small wind tunnel where basic aerodynamic properties such as the lift, drag, and pressure distribution of an airfoil can be measured was used to study an unsteady flow-field around an isolated airfoil. Transparent walls enabled the application of PIV (Particle Image Velocimetry) so as to acquire a 2D velocity-field around the considered airfoil. A study was performed at various angles of attack (AOA). No separation was observed at low AOA. At 10° AOA, the separation vortex comprised 50 % of the airfoil’s chord-length, whilst complete stalling of the airfoil occurred at 20° AOA. The observed separation zone was not fixed but was found to oscillate around its mean-position at an interval of ± 10 % of the chord’s length.

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