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G. Constantinescu, R.C. Ciobanu
Dielectric Relaxation Spectroscopy Of Polyethylene/Lignocellulosic Polymers Blends

Polymer blends of recycled high density poly(ethylene) (RPE) and wood flour (WF) have been prepared by using 3 types of compatibilizing agents. Dielectric relaxation spectroscopy measurements have been carried out by performing temperature sweeps at constant frequency and frequency sweeps at constant temperature. Incorporation of natural polymers and compatibilizing agent in the polyolefin matrix leads to an increase of conductivity and consequently of the dielectric loss values when comparing with those of matrix.

Marius Pislaru, Alexandru Trandabat, Stefan Ursache
Fuzzy Expert System For Power Quality Assessment

This paper describes a fuzzy expert system in order to understand and deal with power quality problems encountered in distribution systems in a better way. Because of the technology and software now available this monitoring is highly effective, the fuzzy expert system not only can provide information about the quality of the power and the causes of power system disturbances, but it can identify problem conditions throughout the system before they cause widespread customer complains and equipment malfunctions. The loads in customer premises have also been the source of power quality problems. It has become important for the utilities to understand the causes for power quality problems and find ways to avoid them. The fuzzy expert system can be used in a utility for personnel training and customer education.

Marius Pislaru, Alexandru Trandabat, Marius Olariu
Neuro Fuzzy System For Industrial Processes Fault Diagnosis

In the last decade considerable research efforts have been spent to seek for systematic approaches to Fault Diagnosis (FD) in dynamical systems The problem of fault detection consists in detecting faults in a physical system by monitoring its inputs and outputs .Recently, the research has focused on non-linear systems FDI. Traditionally, the FD problem for non-linear dynamic systems has been approached in two steps. Firstly, the models linearized at an operating point, and then robust techniques are applied to generate residuals. This method only works well when the linearization does not cause a large mismatch between linear and non-linear models and the system operates close to the operating point specified. To deal with systems with high non-linearity and wide operation range, the FD problem has to be tackled directly using non-linear techniques. In the last decade considerable research efforts have been spent to seek for systematic approaches to Fault Diagnosis in dynamical systems.

Radu Damian, Romeo Ciobanu, Marius Brînzila, Marius Olariu
Stability considerations and efficient computing in chiral materials electromagnetic simulations

A solution for the computational efficiency/accuracy compromise is searched for the electromagnetic simulation of a hexachiral honeycomb. Convergence stability is investigated for the frequency and time domain solvers, and an optimum solution (FDTD analysis in parametric studies with frequency simulation as a permanent reference) is found.

A. Baccigalupi, A. Liccardo
Performance Assessment of “Field Programmable Analog Arrays”

Field Programmable Analog Array (FPAA) are reconfigurable analog modules introduced on the electronic market in the last decade. Their working and, in particular, their programmability is achieved owing to the use of switched capacitors technology. At least in principle, they seem to be a very attractive and powerful tool to design analog circuits whose parameters have to be tuned to signal variations as in carrying out sensor conditioning systems. But, the aim of exploiting their possibilities in the field of metrology requires a complete characterization and performance assessment of the involved building blocks. With this goal, in the paper, the metrological characterization of the most commonly blocks to be used in analog conditioning circuits, such as amplifiers and filters, is performed. These blocks have been characterized in terms of both frequency response and step response and the obtained experimental results have been compared with the ones expected from theoretic analysis. Concluding remarks are then deduced to furnish practical hints in the use of FPAAs in measurement applications.

Warsza Zygmunt Lech, Dorozhovets Mykhaylo, Korczynski Marian Jerzy
Methods of upgrading the uncertainty of type A evaluation. Elimination the influence of unknown drift and harmonic components

A new approach to upgrading the type A uncertainty evaluation by investigation the trend and periodical systematic components in the regularly in time performed observations is presented in the paper. This is a part of best practice, which authors recommend as upgrading the routine procedures in uncertainty evaluation according to ISO GUM recommendation. The cleaning of raw data set by elimination the systematic components and the influence of these cleanings on standard uncertainty is presented and disused. Two numerical examples are discussed.

Ion Sandu, Livia Dragomir, Brândusa Pantelimon
Interlaboratory comparison

This paper presents the results of the “Inter-laboratory comparison” in the pressure field. The comparison refers to the manometers with elastic element, in air, in the range (0 … 2.5) bar. The pilot laboratory was National Institute of Metrology, and the participated laboratories were from industry companies. The main goal was to demonstrate the capabilities of the industry laboratories and competence of these laboratories to supply pressure unit.

Livia Dragomir, Ion Sandu, Brândusa Pantelimon
Consideration regarding the quality of the results of the measurement

The estimation of measurement uncertainty is a compulsive task of each metrological laboratory which has implemented the quality system. This paper presents the main factors that influence the quality of the measurement and the importance of the inter-laboratory comparison.

Christos Christopoulos
The Role of Simulations in Support of Measurements at High-Frequencies

The complexity of interactions at high-frequencies requires the full range of analytical, numerical and experimental techniques to be employed to get a thorough understanding and quantification of observations. The all too often perceived dichotomy between “theory” and “measurements” is unfortunate and does not help the serious investigator. The paper attempts to show how measurements and numerical simulations in complex systems are complementary approaches and should be used together to enhance understanding.

Pasquale Arpaia, Pasquale Cimmino, Fabrizio Clemente, Antonio Panaggio
A real-time non-invasive system monitoring haemodynamic parameters in critical conditions by peripheral blood pressure wave analysis

A non-invasive measurement platform for peripheral blood pressure monitoring and integrated diagnosis based on a piezo film pulse sensor and suitable processing algorithms running on a laptop PC has been developed. Different parameters (such as cardiac output and systolic pressure variation) for integrated haemodynamic management in critical conditions are determined by using mathematical and/or physiopatological models. Moreover, once connected to classical patient monitors, the system computes further parameters used for haemodynamic assessment of critical patients. Experimental results of the clinical in-vivo validation in operating theatres and in intensive care units are reported.

Page 799 of 936 Results 7981 - 7990 of 9356