Esperienze di partecipazione attiva delle studentesse e degli studenti al processo di decision-making: l’emozione della democrazia a Scuola-Città Pestalozzi

Scuola-Città Pestalozzi, fin dalla sua origine, ha organizzato la scuola in una comunità educante in cui la partecipazione attiva degli studenti al processo di decision-making è sempre stata al centro del piano dell’offerta formativa. La scuola all’inizio era organizzata come una vera e propria città in cui a rotazione ogni funzione, dal sindaco al pubblico ministero, dall’assessore al giardiniere, era coperta da studenti e studentesse. Oggi quell’organizzazione è cambiata, si è trasformata, sono rimasti però i paradigmi pedagogici di quell’esperienza. Il contributo che proponiamo è quello di raccontare le esperienze di oggi rispetto alla partecipazione attiva delle studentesse e degli studenti al processo di decision- making

Reduction of Torque Ripple in Synchronous Reluctance Machines through Flux Barrier Shift

Synchronous Reluctance (SyR) machines are a viable alternative to other kinds of electrical machines in many fields. The simple rotor structure allows a high efficiency level with low manufacturing costs and higher safety in high-speed operations. However, one of the main problems of the SyR machines is the torque ripple generated by the interaction of the stator and rotor Magneto-Motive Force harmonics. Many design solutions have been proposed to date, but heavy torque ripple reduction has only been achieved with long optimizations runs or with complex machine structures. This paper presents an easy and effective method to reduce torque ripple through flux barrier shift. Two machines were designed in order to compare the proposed design with a state-of-the-art procedure. The machines designed with flux barrier shift presents similar performances to the optimized machine, with a lower design time and a more general design method

A tool to plan photon-in/photon-out experiments: count rates, dips and self-absorption.

A program that helps to plan experiments where the emitted X-rays are detected is presented. The tool is based on the standard formula for fluorescence-detected X-ray absorption spectroscopy and uses tabulated parameters to estimate count rates. The objective is to evaluate the feasibility of an experiment, estimate the influence of self-absorption on the spectral shape and investigate the possibility of range-extended EXAFS. The occurrence of `negative' edges, i.e. a decrease in the detected signal, is discussed

The Sound of Batteries: An Operando Acoustic Emission Study of the LiNiO2_{2} Cathode in Li–Ion Cells

The development of advanced Li‐ion batteries relies on the implementation of high‐capacity Ni‐rich layered oxide cathode materials, such as NCM and NCA, among others. However, fast performance decay because of intrinsic chemical and structural instabilities hampers their practical application. Hence, thoroughly understanding degradation processes is crucial to overcome current limitations. To monitor instabilities of electrode materials under realistic operating conditions, the application of nondestructive operando techniques is required. While structural changes of crystalline phases can be studied by X‐ray diffraction, microstructural changes (e. g., particle fracture) cannot be easily accessed in situ and are therefore mostly investigated ex situ. Here, we use acoustic emission (AE) measurements to probe a potential next‐generation cathode material in real‐time. Specifically, we focus on LiNiO$_{2}$(LNO) and demonstrate that AE events in different frequency ranges can be correlated with the formation of the cathode solid‐electrolyte interphase and the mechanical degradation during electrochemical cycling

Surface Modification Strategies for Improving the Cycling Performance of Ni-Rich Cathode Materials – Surface Modification Strategies for Improving the Cycling Performance of Ni-Rich Cathode Materials

Ni‐rich layered lithium metal oxides are the cathode active materials of choice for high‐energy‐density Li‐ion batteries. While the high content of Ni is responsible for the excellent capacity, it is also the source of interfacial instability, limiting the material\u27s lifetime due to a variety of correlated in‐ and extrinsic factors. Hence, reconciling the opposing trends of high Ni content and long‐term cycling stability by modifying the material\u27s surface is one of the challenges in the field. Here, we review various studies on surface modification of Ni‐rich (≥ 80 %) layered cathode active materials in order to categorize current research efforts. Broadly, the three strategies of coating, surface doping and washing are discussed, each with their advantages and shortcomings. In conclusion, we highlight new directions of research that could bring Ni‐rich layered lithium metal oxide cathodes from the laboratory to the real world