Power Converters and Electric Drives for Smart Grid Applications

The present dissertation aims to explore, theoretically and experimentally, the problems and the potential advantages of different types of power converters for “Smart Grid” applications, with particular emphasis on multi-level architectures, which are attracting a rising interest even for industrial requests. The models of the main multilevel architectures (Diode-Clamped and Cascaded) are shown. The best suited modulation strategies to function as a network interface are identified. In particular, the close correlation between PWM (Pulse Width Modulation) approach and SVM (Space Vector Modulation) approach is highlighted. An innovative multilevel topology called MMC (Modular Multilevel Converter) is investigated, and the single-phase, three-phase and "back to back" configurations are analyzed. Specific control techniques that can manage, in an appropriate way, the charge level of the numerous capacitors and handle the power flow in a flexible way are defined and experimentally validated. Another converter that is attracting interest in “Power Conditioning Systems” field is the “Matrix Converter”. Even in this architecture, the output voltage is multilevel. It offers an high quality input current, a bidirectional power flow and has the possibility to control the input power factor (i.e. possibility to participate to active and reactive power regulations). The implemented control system, that allows fast data acquisition for diagnostic purposes, is described and experimentally verified

Quintuplices sacrae quadragesimales inuentiones

ColofónSign.: a-c\p4\s, A-Z\p8\s, 2A-2H\p8\s, 2I\p6\sGrab. xil. en por

Executive Transitions: Grantmakers and Nonprofit Leadership Change

Even for seasoned funders, supporting leadership transitions can be a tricky business. Where is the fine line between helping and intruding? What interventions work? And how can a grantmaker play a constructive role? Learn how grantmakers take up the transition challenge, engage with boards, support new CEOs, and help grantees use the moment to go in promising new directions.HighlightsSupporting exiting and incoming CEOsWhen a board member callsNurturing the next generation of leadersWhat's in the Guide?The Grantmaker's Role in Leadership Transitions:Grantmakers care deeply about the quality of leadership in the organizations they support. But what can they do to help their own grantees, and perhaps even other organizations, manage executive transitions successfully?Assisting Organizations in Transition: Money and More: Nonprofits need funding during transitions as much as they ever do - maybe more. Foundations can help with that, of course, but they can also offer other types of support, such as information, encouragement, and specialized services.Making Common Cause with the Board: Replacing an executive director is a serious responsibility for a nonprofit board. Grantmakers can assist by being responsive, even proactive, during what often turns into a challenging process.Supporting Exiting and Incoming CEOs: Executive transitions have a personal side. Grantmakers can ease the departure of an exiting CEO or help a newcomer get off to a strong start with a few simple gestures and practical steps.Opening the Way for New Leaders: A wide range of strategies are available to expand, strengthen, and diversify the base from which future executive directors will come

Competenze socioemotive a scuola: risultati preliminari di un programma di potenziamento del Social Problem Solving in bambini di 8 anni

Lo studio presenta i risultati preliminari della ricerca-intervento “CoSE a scuola” mirato al potenziamento delle competenze sociali in bambini di classe terza primaria, seguendo l’approccio teorico del Social Information Processing (Crick & Dodge, 1994). L’intervento prevede incontri per gli insegnanti che vengono formati a condurre laboratori sul Social Problem Solving in classe con i bambini. Hanno partecipato allo studio 115 bambini (età media 8,3 anni), di cui 54 appartenenti al gruppo sperimentale, che ha preso parte all’intervento, e 61 appartenenti al gruppo di controllo, sottoposto solo alla valutazione. I risultati mostrano che i bambini che hanno partecipato all’intervento nel post-test mostrano più capacità, rispetto al pre-test, di scegliere strategie comportamentali più competenti.The present study shows some early results of “CoSE a scuola”, an intervention-research aimed to improve the social competence of children at school, following the Social Information Processing theoretical model (Crick & Dodge, 1994). During the intervention, the teachers learned how to conduct laboratories in class with children, to teach them Social problem solving skills. Social problem solving assessment was administrated to 115 children (mean age 8,3 years), divided in an intervention group (N = 54) and a control group (N =61). The results showed that children in intervention group improved their Social problem solving Skills

Reductive arylation of maleic and fumaric acid derivatives by arenediazonium and titanium(III) salts

Arylation of RCH:CHR (R = CO2H, CN, CONH2, CO2Me) with R1N2+ BF4- (R1 = Ph, o-, m-, p-ClC6H4, p-anisyl, p-BrC6H4, p-FC6H4) in the presence of Ti3+ gave 52-73% 12 RR1CHCH2