Search results for "TTR"
showing 10 items of 3945 documents
La migrazione studentesca dalla Laurea Triennale alla Laurea Magistrale
2017
In the last years, the Italian universities have experienced significant changes that involve the students and the universities' governance. Students' enrolment has decreased significantly especially after the economic crisis of 2008, while the students' migration from the South to the Central and Northern regions of the country has increased. This phenomenon has created further inequalities within the country and a cultural and socio-economic loss for the South. Important changes have pushed the universities also compete to attract students. Therefore, among the others, student migration is an issue that needs full consideration. In this paper, the attention is devoted to the First Level g…
Fuel cell analytical modeling: Solving the trade-off between accuracy and complexity
2013
In this paper, a 5.5 kW Proton Exchange Membrane fuel cell is modeled. The proposed analytical model is described and the parameters identification procedure is further discussed. Simulation results of all three sub-models are compared to test the accuracy of each one. A comparison between simulation and experimental results is provided as well validating the modeling approach.
Design and realization of a DC/DC converter with a partially saturated inductor
2017
DC/DC converters, in some types of applications such as portable equipments, can require more space than it is actually available. The inductor is typically the most bulky element and the possibility to reduce its size can save up to 50% of the converter volume and area [1][2], thus increasing the power density. This reduction, however, comes with nonlinear effects caused by the saturation of the ferromagnetic core. An appropriate modelling of the inductor and of the converter circuit is needed for guaranteeing a good output power quality (Fig. 1). A Boost converter with an inductor in the partially saturated roll-off operating zone was designed and realized to study the behaviour of DC/DC …
Non-Linear Inductor Models Comparison for Switched-Mode Power Supplies Applications
2022
The use of non-linear power inductors, intended as devices exploited up to a current at which the inductance is halved, is of great interest in switched-mode power supplies (SMPSs). Indeed, it allows the use of lighter and cheaper inductors improving the power density. On the other hand, the analysis of SMPSs equipped with non-linear inductors requires appropriate modeling of the inductor reproducing the inductance versus current. This paper compares two main analytical models proposed in the literature: the former is based on a polynomial, and the latter exploits the arctangent function to reproduce the non-linearity of the inductance. Performance is compared by considering the effort of r…
Analisi numerica degli effetti della deformazione di membrane a scambio ionico sulla distribuzione dei fluidi in canali di Elettrodialisi
2019
L’elettrodialisi (ED) è una promettente tecnologia a membrana utilizzata in diversi campi, ad esempio nella dissalazione delle acque e nell’industria alimentare. L’ED usa un potenziale elettrico per indurre una migrazione selettiva di cationi ed anioni da una soluzione elettrolitica ad un’altra, sfruttando membrane a scambio ionico. Membrane anioniche e cationiche sono alternativamente collocate all’interno di una unità ED. A queste sono solitamente interposti spaziatori che prevengono il contatto tra le membrane e delineano i canali in cui scorrono le soluzioni. L’utilizzo di membrane profilate consente di costruire unità prive di tradizionali spaziatori a rete non conduttivi. In genere, l…
Social identification and group cohesiveness in a multicultural work group
2001
Opettajan attribuutiot opetussuunnitelman toteuttamisessa
2001
Design and Performance Evaluation of a High Power-Density EMI Filter for PWM Inverter-Fed Induction-Motor Drives
2016
This paper presents the design of an electromagnetic interference (EMI) filter for a low-voltage high-current induction-motor drives supplied by dc power grids. In order to effectively design the EMI filter, a suitable common-mode/differential-mode (CM/DM) separation technique has been used. Due to the high operating currents, the software-based separation technique using time-domain measurements has been applied. The proposed technique allows the CM and DM sections of the EMI filter to be properly selected in a more economical way, i.e., without the need of a dedicated hardware or costly radio frequency (RF) instrumentation. The design has been done according to a power-density criterion. …
Peruskouluikäisten kehityksellisen koordinaatiohäiriön pysyvyys ja sen yhteys oppimisvaikeuksiin ja koulutyöskentelytaitoihin
2010
Recensione di Religione e diritti umani nell'Italia multiculturale
2021
Quello dei diritti umani, trattato nella fattispecie della libertà religiosa, è un argomento sotto molti profili profili complesso e delicato. Se ne occupano in questo volume Sara Lagi, Chiara Maritato e Roberta Ricucci, mettendo in campo con cura le proprie metodologie di indagine scientifiche e offrendone così un puntuale e sistematico approfondimento per il tramite di un approccio storico-politico e sociologico che converge soprattutto sul contesto italiano contemporaneo.