86,566 research outputs found
Bach J.-F., Houdé O., Léna P., Tisseron P. - Académie des Sciences - (2016). Ed. it. a cura di P. Ferri, S. Moriggi. Il bambino e gli schermi. Raccomandazioni per genitori e insegnanti. Milano: Guerini Scientifica.
No full textCorpus delle iscrizioni bilingui aramaico nabateo-greche. Approfondimenti onomastici e problemi di ricostruzione del sistema fonologico del nabateo
No full textIl campo di ricerca della tesi di Dottorato riguarda la costituzione di un corpus di iscrizioni bilingui aramaico nabateo-greche. Lo studio prende le mosse dall’assenza, allo stato attuale, di una silloge che include le suddette epigrafi dell’area mediterranea e vicino orientale dal I secolo a.C. al III secolo d.C. Questo permette di approfondire gli aspetti morfosintattici e lessicali peculiari delle due aree linguistiche (nabatea e greca) e di gettare uno sguardo complessivo sulle modalità di scambio culturale (sociale, politico e religioso) tra le realtà semitica occidentale ed ellenica. Infine, la parte più rilevante della ricerca riguarda l’analisi comparativa dell’onomastica nabatea e greca, attestata nelle bilingui, e l’indagine onomastica nabatea di iscrizioni monolingui, al fine di ricostruire la fonetica dell’aramaico nabateo
Chemical functionalization of graphene surface as filler for rubber compounds
No full textOver the last few years, the surface modification of fillers for high-level technological applications such as polymer composites for tyre industry, conductive inks and coatings has seen a considerable increase in interest since it can increase mechanical, electrical, and thermal properties of the final material. Nano-sized carbon allotropes such as graphene and carbon nanotubes are a suitable class of compounds for these purposes: high thermal and electrical conductivity along with considerable mechanical reinforcement are the main improvements that these fillers bring to the composite and their elevated surface area allows to reduce the filler volume ratio compared to more common alternatives. An efficient and reliable method to modify the surface of these nano-fillers is the so-called pyrrole methodology, a mild procedure that involves bio-sourced reagents to introduce functional groups on the graphitic planes and that has been recently employed in the fabrication of elastomeric composites with improved mechanical properties. In order to understand the mechanism beneath the interaction between the pyrrole and the substrate and thus the behavior of the functionalized filler, a more in-depth analysis is requested. A theoretical work based on molecular dynamics simulations and a DFT study were performed in order to investigate the interaction energy, the geometry of interaction and the mobility of N-substituted pyrrole molecules adsorbed on the graphene planes. This theoretical study at atomistic level can help design a new class of high-performance fillers by better understanding the interaction mechanism given the important role of supramolecular interactions
Model Predictive Control Strategies for Electric Endurance Race Cars Accounting for Competitors' Interactions
No full textThis letter presents model predictive control strategies for battery electric endurance race cars accounting for interactions with the competitors. In particular, we devise an optimization framework capturing the impact of the actions of the ego vehicle when interacting with competitors in a probabilistic fashion, jointly accounting for the optimal pit stop decision making, the charge times and the driving style in the course of the race. We showcase our method for a simulated 1 h endurance race at the Zandvoort circuit, using real-life data from a previous event. Our results show that optimizing both the race strategy and the decision making during the race is very important, resulting in a significant 21 s advantage over an always overtake approach, whilst revealing the competitiveness of e-race cars w.r.t. conventional ones
Chemical functionalization of graphene surface with pyrrole compounds. Modeling of supramolecular interactions
No full textIn the last decade, the surface modification of fillers for high-level technological applications such as polymer composites for tyre industry has seen a considerable increase in interest since it can boost the properties of the final material. Nano-sized carbon allotropes such as graphene and carbon nanotubes are a suitable class of compounds for these purposes: high thermal and electrical conductivity along with considerable mechanical reinforcement are the main enhancements that these fillers bring to the composite and their elevated surface area allows to reduce the filler volume ratio compared to more common alternatives. An efficient and reliable procedure to tweak the surface of these nano-fillers is the so-called pyrrole methodology, [1] a mild procedure that involves bio-sourced reagents to introduce functional groups on the graphitic planes and that has been recently employed in the fabrication of elastomeric composites with improved mechanical properties [2]. In order to understand the mechanism beneath the interaction between the pyrrole and the substrate and thus the behavior of the functionalized filler, a more in-depth analysis is requested. A theoretical work based on molecular dynamics simulations and a DFT study were performed to investigate the interaction energy, the geometry of interaction and the mobility of N-substituted pyrrole molecules adsorbed on the graphene planes. This theoretical study at atomistic level can help design a new class of high-performance fillers by better understanding the interaction mechanism [3] given the important role of supramolecular interactions.
Results
N-substituted pyrroles and pyrrolidines with increasing carbon atoms in the substituent alkyl chain were adsorbed on a pristine graphene surface. Two main stabilizing effects were found to be relevant: pyrrole sp2 configuration allowed π-π bonding with the graphene surface and longer alkyl chains promoted dispersion interactions. Molecular dynamics was then used to study the behavior of 20 molecules of different pyrroles. Polarity of the nitrogen substituent and temperature were found to be central for the spreading of the substances on the graphene surface
Tecnologicamente abita il bambino. Note epistemologiche per lo sviluppo di una cultura digitale per gli operatori dei nidi e delle scuole dell'infanzia
No full textAnharmonic calculations of vibrational spectra for molecular adsorbates: A divide-and-conquer semiclassical molecular dynamics approach
No full textThe vibrational spectroscopy of adsorbates is becoming an important investigation tool for catalysis and material science. This paper presents a semiclassical molecular dynamics method able to reproduce the vibrational energy levels of systems composed by molecules adsorbed on solid surfaces. Specifically, we extend our divide-and-conquer semiclassical method for power spectra calculations to gas-surface systems and interface it with plane-wave electronic structure codes. The Born-Oppenheimer classical dynamics underlying the semiclassical calculation is full dimensional, and our method includes not only the motion of the adsorbate but also those of the surface and the bulk. The vibrational spectroscopic peaks related to the adsorbate are accounted together with the most coupled phonon modes to obtain spectra amenable to physical interpretations. We apply the method to the adsorption of CO, NO, and H2O on the anatase-TiO2 (101) surface. We compare our semiclassical results with the single-point harmonic estimates and the classical power spectra obtained from the same trajectory employed in the semiclassical calculation. We find that CO and NO anharmonic effects of fundamental vibrations are similarly reproduced by the classical and semiclassical dynamics and that H2O adsorption is fully and properly described in its overtone and combination band relevant components only by the semiclassical approach
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