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Silicone resins are widely adopted in outdoor and indoor electrical equipments. One of the main applications includes medium power rotating machines where they are used for the impregnation of rotor and stator windings. Due to the growing demand for compact insulation, the improvement of heat dissipation in such devices has recently become a very important issue and dielectric materials with enhanced thermal conductivity and, at least, unmodified mechanical and electrical properties are needed. In the present paper, we report results about the preparation and the morphological, thermal, mechanical and electrical characterization of new materials obtained by addition of nano-sized alumina (Al2O3) fillers to silicone matrix. Their measured physical properties are compared with those of the unfilled matrix, used as a reference, and the influence of the weight concentrations, ranging between 1 wt % and 7 wt % is fully discussed.

The aim of the present paper is to investigate on the changes, due to nanoparticles functionalization, of the electric and dielectric properties of epoxy composites filled with alumina (Al2O3) nanoparticles. In particular, results of dielectric spectroscopy, DC volume resistivity, permittivity and dissipation factor at 50 Hz on epoxy samples filled with alumina nano-sized particles at different weight percentages (1%, 3% and 5% wt) are illustrated and commented

Questo articolo analizza il mercato del lusso soffermandosi in particolare sulle caratteristiche principali dei prodotti luxury good. Fondamentali sono: l'unicità, il pregio, la qualità eccellente ed il prezzo elevato. Grazie alla legge di Hengel è stato possibile centrare l'indagine sul diverso andamento incrementale dei beni inferiori, normali e di lusso all'aumento della fascia di reddito da parte dei soggetti. Si è posto l'accento su come il mercato del lusso sia quello maggiormente incrementato da parte dei soggetti di fascia alta. Negli ultimi anni a differenza dei beni inferiori e normali, il mercato dei beni di lusso ha subito un incremento del 35,7%.

Questo articolo si concentra sui mercati emergenti e sul loro rapporto con il mercato dei beni di lusso. Ciascuna economia emergente ha caratteristiche peculiari che rendono il proprio mercato più o meno appetibile per l'investitore estero. Lo studio portato avanti propone una prima parte descrittiva focalizzata sulle economie emergenti ed i loro potenziali di sviluppo futuro. La seconda parte dell'articolo è incentrata sul mercato del lusso nei paesi emergenti e sulle opportunità future di sviluppo di tali mercati. Dalle conclusioni di tale studio emerge che i mercati emergenti si dimostrano essere potenziali mercati strategici per lo sviluppo del settore del lusso.

Partial discharge (PD) measurements provide useful information on the condition of electrical insulation in high and medium voltage components. However, UHF on-line PD measurements are often affected by external noise and disturbances of various nature which can hide the discharge signal and strongly affect the sensitivity and reliability of the measurement. In such a harsh environment, the extraction of partial discharge becomes a fundamental topic. The application of Wavelet Packet Transform (WPT) to extract partial discharge signals buried in excessive noise is described in this paper. The denoising technique, applied to numerical signals, is based on an energy criterion in conjunction with hard-thresholding

In questo articolo si affronta il tema del mercato azionario. Esso ha assunto un ruolo crescente nell'ambito del sistema finanziario. La sua caratteristica più importante è la capacità di rappresentare la situazione in cui si trova l'economia reale. L'andamento del mercato azionario può essere influenzato in larga parte dall'andamento dell'economia reale e di conseguenza dalla fiducia degli investitori. L'andamento degli indici a zionari è in grado, nell'arco temporale 2008/2014, di darci un quadro chiaro delle ripercussioni della crisi finanziaria sul mercato azionario. L'articolo è diviso in due parti. La prima descrive il mercato azionario e i fattori che lo influenzano. Nella seconda parte, analitica, vengono presi in esame i tre indici che più rappresentano il reale andamento del mercato azionario, Ftse - mib, Cac40 e S&P500.

It is well known that lightning discharges follow a tortuous path; therefore, a general technique able to evaluate the electromagnetic (EM) fields associated with discharge currents flowing into tortuous channels seems to be worthy of consideration. Two techniques have been adopted to find the EM field generated by a current pulse traveling along a single line radiator with arbitrary slope and location above the ground. The first one employs the Fraunhofer approximation, which can provide useful information only on distant radiated fields. The second technique is exact, but applies only to the case of a velocity of propagation v of the current pulse equal to c (velocity of light). Even this solution is indeed inadequate for our purposes since v

A description of the experimental and theoretical investigations, carried out for the realization of a cryogenic cable termination, is presented. Identification and classification of the partial discharge (PD) patterns obtained on an HV vacuum bushing and on two types of cable model insulation was attempted. It is shown how a methodological and proper interpretation of experimental data can provide information on the design of cryogenic devices as well as indications on their optimal operating conditions

The lightning processes are always initiated by significant intracloud electrical activities whose amplitude is much higher than the so-called atmospheric noise (atmospherics) [1]. Therefore, disturbances and interferences are induced in on-board electronic systems belonging to aircrafts flying in the vicinity or inside the clouds. In this paper the electromagnetic field generated by intracloud prebreakdown activity, simulated by adopting the model described in [5], is evaluated everywhere (inside and outside the cloud). This can be considered the starting point for the evaluation of the whole interference on the electronic on-board devices once the presence of the aircraft is considered.

In acceptance testing of dry type, resin insulated instruments (voltage) transformers different partial discharges characteristics may be obtained by adopting the two arrangements suggested in the IEC 44-4 standard. Although the electric field distribution inside the component does not significantly depend on test arrangement, different partial discharge results are obtained. The unlike behaviours obtained by adopting the two set-ups are presented and explained. Some criticism to the present form of the standard is raised and suggestions of improvement are presented

In this paper experimental and theoretical activities carried out on the setup of a station for testing a High Voltage (HV) superconducting model cable are presented. Great attention is dedicated to the methodological use of experimental data for the characterization of the apparatus. In particular, it is shown how partial discharge measurements can give significant suggestions to the designer on how to exploit the realisation of the station as well as indications on the optimal operating conditions of the device.