Search results for "MISURE"
showing 10 items of 496 documents
DC series arc faults in PV systems. Detection methods and experimental characterization
2020
This work is focused on the arc faults phenomenon in DC photovoltaic (PV) systems. The paper gives an overview of arc detection methods proposed in literature and presents a preliminary experimental characterization of the arcing current, focusing the attention on series arcs, whose detection is particularly challenging. Experimental tests are carried out, both in laboratory and on field, in order to investigate some relevant characteristics in the arcing current, which can be feasible for the arc detection purpose. Both arcing and non-arcing current signals are acquired and compared in both time and frequency domain. On-field measurements are carried out on a real photovoltaic system, in a…
An Experimental Characterization of Time of Arrival Accuracy for Time Synchronization of Medium Voltage Smart Grid Solutions
2019
The time synchronization of smart grid devices is a critical feature for the successful application of advanced grid monitoring and control techniques. Synchronization mechanisms based on the accurate estimation of the Time of Arrival (ToA) of network messages - sent over power line cables - are a promising solution to achieve synchronization tasks over distribution lines. In this paper, a chirp-based synchronization technique over the Medium Voltage (MV) grid has been proposed and characterized. Such approach has the benefit of not requiring the installation of a dedicated infrastructure, thanks to the exploitation of power distribution lines for the transmission of time synchronization da…
La riforma ponderale del Piazzi e le misure utilizzate dagli argentieri siciliani.
2009
Il saggio è il primo capitolo di un lavoro più complessivo sull'evoluzione dei sistemi ponderale predecimali nel quale, avvalendosi di fonti documentarie diverse da quelle tradizionalmente usate per ricerche di tal genere, si affrontera' la tematica dell'evoluzione del sistema ponderale come strumento per la formazione dello stato moderno. In questo saggio si delinea il conflitto della Deputazione dei Pesi e Misure con la corporazione degli argentieri in occasione della riforma ponderale del 1809.
Generation of oxygen deficient point defects in silica by γ and β irradiation
2007
We report an experimental study of the effects of y and β irradiation on the generation of a point defect known as ODC(II) in various types of commercial silica (a-SiO 2 ). The ODC(II) has been detected by means of photoluminescence (PL) spectroscopy measuring the PL band centered at 4.4 eV and excited at 5.0 eV associated to this defect. Our experiments show that ODC(II) are induced in all the investigated materials after irradiation at doses higher than 5 x 10 2 kGy. A good agreement is observed between the efficiencies of generation of ODC(II) under y and β irradiation, enabling a comprehensive study up to the dose of 5 x 10 6 kGy. Two different growth rates, one in the low and one in th…
Equivalent detector models for the simulation of efficiency response of an HPGe detector with PENELOPE code
2019
In this work, some ‘equivalent’ models for the simulation of efficiency response of a High-Purity Germanium (HPGe) detector, installed inside a ‘low background’ bunker in the Engineering Department of the University of Palermo, were developed. The main feature was to attribute the uncertainties of the model to only one of the parameters, the dead layer of the detector, keeping unchanged the other data provided by the manufacturer. With this technique, using the Monte Carlo PENELOPE code in the 2011 version, the efficiency response was evaluated and compared with the previous one performed with MCNP5 code. The validation of equivalent models is performed by comparing the simulation results w…
MCNP5 modelling of HPGe detectors for efficiency evaluation in gamma-ray spectrometry
2009
A modelling of HPGe detectors was performed through simulation with the MCNP5 Monte Carlo code. The simulation results concerning the values of the main physical parameters of the detector are in most cases different from those provided by the manufacturer. The use of “single-line” sources allows us to suitably modify the parameter values used in the detector model. For a detector model, the simulation assesses the distribution of photopeak and total efficiency for point sources, whereas for extended sources a control volume approach allows us to determine elementary efficiency behaviours. An integration of elementary efficiencies over the entire sample volume allows us to evaluate global e…
Virtual point detector: Application to coincidence-summing correction in gamma-ray spectrometry
2009
The use of an efficiency transfer method based on the virtual point detector approximation to evaluate coincidence-summing correction values for point and volume sources was examined. The method was validated by means of a comparison with experimental efficiency determinations.
Measurement of radionuclide activities induced in target components of an IBA CYCLONE 18/9 by gamma-ray spectrometry with HPGe and LaBr3: Ce detector…
2014
Cyclotrons are used worldwide to produce radiopharmaceuticals by proton irradiation of a suitable target. The intense secondary neutron beam generated by proton interactions with the target induce high radionuclide activities in the target assembly parts that may result in an exposure to high dose levels of the operators during maintenance. The main goal of this work is to evaluate gamma-emitting radionuclide activities induced in Havar foils and titanium windows of a target assembly and carousel stripper forks of an IBA CYCLONE 18/9 cyclotron. The knowledge of radionuclide inventory for each component is required by many companies to assess risk for operators before waste handling and disp…
Reduction of the uncertainty in the measurements of magnetic fields
2014
The paper deals with magnetic field measurement, carried out by using a broadband and isotropic instrument. These measurements are characterized by a very high uncertainty values if compared with the ones usually related to other electrical measurements. For these reasons, if the measurements are performed to assess the exposure of human beings, these large uncertainty values imply a high risk of wrong decision when there is the need to establish if a site complies or does not comply with a specified emission limits. A reduction of the uncertainty values implies a reduction of the risk. With this aim, we propose an approach which, in particular but very typical cases, allows an effective re…
Characterization and Error Compensation of a Rogowski Coil in the Presence of Harmonics
2011
This paper reports the results of an experimental study dealing with a commercial Rogowski coil current transducer (RCCT) in the presence of harmonic distortion. The RCCT was observed under two conditions: 1) sinusoidal excitation with frequencies from 50 to 750 Hz and 2) nonsinusoidal excitation using fundamental frequency and one harmonic, with adjustable amplitude and phase shift. The experimental results show only a weak dependence of the harmonic current ratio error and phase displacement on the amplitude and phase shift of the excitation harmonic. The phase displacement is also independent of the conductor position within the Rogowski coil window. An error compensation method, based o…