370 research outputs found
Pyr1,xtfsi ionic liquids (X = 1–8): A computational chemistry study
No full textPyrrolidinium-based (Pyr) ionic liquids are a very wide family of molecular species. Pyrrolidinium cations are electrochemically stable in a large potential interval and their molecular size hinders their transport properties. The corresponding ionic liquids with trifluoromethyl sulphonyl imide anions are excellent solvents for lithium/sodium salts and have been demonstrated as electrolytes in aprotic batteries with enhanced safety standards. In this study, the analysis of the physicochemical properties of a homologous series of pyrrolidinium-based ionic liquids with general formula Pyr1,xTFSI (x = 1–8) have been tackled by first principles calculations based on the density functional theory. The molecular structures of isolated ions and ion pairs have been predicted by electronic structure calculations at B3LYP level of theory in vacuum or in simulated solvents. Thermodynamic properties have been calculated to evaluate the ion pairs dissociation and oxidation/reduction stability. This is the first systematic computational analysis of this series of molecules with a specific focus on the impact of the length of the alkyl chain on the pyrrolidinium cation on the overall physicochemical properties of the ion pairs
Performances of different DFT functionals to calculate the anodic limit of fluorinated sulphonyl-imide anions for lithium cells
No full textIn this paper we investigated the calculation of the anodic limit of two anions of ionic liquids, largely used as electrolyte of lithium batteries. Starting from a model based on calculations performed on single ions at the MP2 level of theory, we showed that the matching between calculation and experiments decreases while using more expanded basis set with respect to 6-31G**, possibly because of the destabilization of the neutral species when larger basis sets are considered. Additionally, in order to decrease the computational time, the performances for the calculation of the anodic limit obtained by means of a series of DFT functionals with increasing level of complexity (from the Generalized Gradient Approximation to the Range Separated Hybrid meta–Generalized Gradient Approximation) were compared. Overall, the best performing functionals are BMK, ωB97M-V and MN12-SX, while acceptable results can be obtained by M06-2X, M11, M08-HX and M11-L. Some less computationally expensive functionals, like CAM-B3LYP and ωB97X-D, also provide reasonable values of the anodic limit
A gas-inlet system coupled with a Knudsen cell mass spectrometer for high-temperature studies
No full textgas-inlet system coupled with a Knudsen effusion mass spectrometer has been developed to study at high temperature the interaction of solids and vapors with reactive permanent gases, such as H2 and O2, directly introduced into the cell from external low-pressure reservoirs (pressure range: 10-4 < p < 1 bar). By selecting the gas flow from the external reservoir the pressures of the gases inside the Knudsen cell can be quantitatively controlled over three orders of magnitude, approximately from 10-8 to 5.10-5 bar. Mixtures of two different gases can be introduced into the cell, controlling their partial pressures independently. The capabilities of the device have been tested with four gas-solid systems: PbO(s) + O2(g), GeO2(s) + O 2(g), Ga(s) + H2(g) and Au(s) + H2(g), by studying the relevant high-temperature equilibria. The results obtained for the dissociation energies of the diatomic molecules PbO(g), GeO(g), GaH(g), and AuH(g) compare well with the literature data giving confidence in the reliability and versatility of the method. Preliminary experiments on the in situ formation of H2O(g) in the Knudsen cell by the introduction of controlled gaseous H2/O2 mixtures are also presented
Aprotic sulfur-metal batteries: lithium and beyond
No full textMetal-sulfur batteries constitute an extraordinary research playground that ranges from fundamental science to applied technologies. However, besides the widely explored Li-S system, a remarkable lack of understanding hinders advancements and performance in all other metal-sulfur systems. In fact, similarities and differences make all generalizations highly inconsistent, thus unavoidably suggesting the need for extensive research explorations for each formulation. Here we review critically the most remarkable open challenges that still hinder the full development of metal-S battery formulations, starting from the lithium benchmark and addressing Na, K, Mg, and Ca metal systems. Our aim is to draw an updated picture of the recent efforts in the field and to shed light on the most promising innovation paths that can pave the way to breakthroughs in the fundamental comprehension of these systems or in battery performance
La telefonia mobile. Profili giuridici. Il diritto in azione. Collana diretta da Salvatore Sica e Pasquale Stanzione.
No full textThe work's aim is to analyse the consumer protection in mobile phone arena. According to the fast development of mobile media technologies, the author provides a survey and offers some solutions to the main legal problems outlined by the emerging contractual models as well as by unfair terms or practices
'Formulae de dolo' e dolo processuale tra la fine della repubblica e gli inizi del principato
No full textStructural Files LRLO antisites
No full textThis database consists in the POSCAR files used as input files for DFT calculations to investigate antisite defects in LRLO materials. Li-rich layered oxide (LRLO) materials are extensively studied as promising positive electrode materials for Li-ion batteries. The formation of Li/Ni antisite defects in the layered lattice of the Co-free LRLO Li1.2Mn0.6Ni0.2O2 compound is here investigated. Antisite defects involving transition metals (TMs), preferentially nickel, and lithium ions occurs spontaneously in many LRLO but their impact on the functional properties in batteries is controversial.Here we propose a simple thermodynamic model to evaluate the concentration of antisite defects in the rhombohedral lattice of the Li1.2Mn0.6Ni0.2O2 as a function of temperature. This model is based on defect formation thermodynamics derived from density functional theory (DFT) calculations performed on disordered supercells. Our aim is to shed light on the native disorder in LRLO and how the synthesis protocol can promote the antisite defect formation.Computational Data were acquired using VASP (Vienna Ab inito simulation packaging) within the Kohn-Sham density functional theory (DFT) framework. We used the DFT+U method. Analysed/processed Dat
Responsabilità civile e attori secondari. Il caso della scheme liability tra esperienza statunitense e dibattito europeo. Temi di Diritto Privato e di Diritto Pubblico, collana diretta da Guido Alpa.
No full textThe work deals with liability for financial misstatements in an original perspective. According to the recent U S experience this kind of liability seems to be limited to primary violators of relevant disclosure duties. The possibility of an extension to third parties is here investigated in a comparative perspective
Court-ordered Apologies: A View of the Italian Legal System
No full textThe article analyses the issue of the possibility of a Court-ordered apology, as a form of compensation for moral damages in the Italian legal system. Assuming that the judgment can be based on the rule of the civil code that allows compensation in specific form (art. 2058), this possibility is investigated in the light of a double perspective. First, the hypothesis that the compensation in specific form of non-pecuniary damage (art. 2059, civil code) is admissible is examined. Once this perspective is admitted, some limits that could affect apologies arise. As a performance, object of the compensation obligation, apologies could be found incompatible with some constitutional guarantees (right to freedom of expression, due process clause). Finally, the author points out, thanks to a comparative argument and the reference to recent German doctrine, the admissibility of a solution, based on the claimant's request to issue a judgment of an alternative and optional nature (between a sum of money, as moral damages, and apologies)
Conversational Speech Separation: an Evaluation Study for Streaming Applications
No full textContinuous speech separation (CSS) is a recently proposed framework which aims at separating each speaker from an input mixture signal in a streaming fashion. Hereafter we perform an evaluation study on practical design considerations for a CSS system, addressing important aspects which have been neglected in recent works. In particular, we focus on the trade-off between separation performance, computational requirements and output latency showing how an offline separation algorithm can be used to perform CSS with a desired latency. We carry out an extensive analysis on the choice of CSS processing window size and hop size on sparsely overlapped data. We find out that the best trade-off between computational burden and performance is obtained for a window of 5 s
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