438 research outputs found
Erratum: Influence of the conditions of sensitization on the characteristics of p-DSCs sensitized with asymmetric squaraines (Journal of the Electrochemical Society (2017) 164 (H1099) DOI: 10.1149/2.0971714jes)
No full textReference 41 should appear as: 41. M. Bonomo, C. Magistris, R. Buscaino, A. Fin, C. Barolo, and D. Dini, Chemistry Select, 3, 1066 (2018)
Synthesis and crystal structure of Bis(2-phenylpyridine-C,N’)-bis(acetonitrile) iridium(III)hexafluorophosphate showing three anion/cation couples in the asymmetric unit
No full textThe title compound bis(2-phenylpyridine-C,N’)-bis(acetonitrile)iridium(III)hexafluorophosphate, a six-coordinate iridium(III) complex, crystallizes in the P-1 space group. Iridium is in a distorted octahedral (n = 6) coordination with the N,C’ atoms of two phenylpyridine and the N atoms of two acetonitrile ligands. The peculiarity of this structure is that three independent moieties of the title compound and three PF6− anions, to counterbalance the charge, are observed in the asymmetric unit and this is a rather uncommon fact among the Cambridge Crystallographic Database (CSD) entries. The three couples are almost identical conformers with very similar torsional angles. The packing, symmetry, and space group were accurately analyzed and described also by means of Hirshfeld surface analysis, which is able to underline subtle differences among the three anion/cation couples in the asymmetric unit. The driving force of the packing is the clustering of the aromatic rings and the maximization of acetonitrile:PF6− interactions. The asymmetry of the cluster is the cause of the unusual number of moieties in the asymmetric unit
Modellazione multiscala di celle a combustibile ad ossidi solidi: dalla microstruttura alle prestazioni
No full textIn questo studio si presenta un approccio modellistico integrato per la simulazione di celle a combustibile ad ossidi solidi (SOFC). La modellazione copre in primis gli aspetti microstrutturali degli elettrodi porosi compositi costituenti la cella, le cui proprietà effettive di trasporto e reazione sono predette con la teoria di percolazione e/o con la ricostruzione numerica della microstruttura in funzione di composizione, distribuzione granulometrica delle polveri e condizioni di sinterizzazione. Le proprietà effettive costituiscono i parametri dei modelli di trasporto e reazione all'interno della cella, basati su bilanci di massa e carica, che permettono di ottenere la distribuzione delle variabili di campo e l'efficienza energetica del sistema. L'accoppiamento della modellazione microstrutturale con quella di trasporto e reazione permette di correlare i due livelli di scala cosicché i modelli tra loro integrati sono utilizzati come strumento interpretativo dei dati sperimentali e come strumento per l'ottimizzazione di prestazione e design.In this study an integrated modelling framework for the simulation of solid oxide fuel cells (SOFC) is presented. The modelling firstly covers the microstructural aspects of porous composite electrodes which constitute the cell, whose effective transport and reaction properties are predicted by means of percolation theory and/or numerical reconstruction of the microstructure as a function of composition, particle size distribution and sintering conditions. The effective properties are parameters of the models of transport and reaction within the cell, based on mass and charge conservation balances, which allow to obtain the field variables distribution and the energetic efficiency of the system. Coupling the microstructural modelling with the transport and reaction modelling enables the correlation of the two different scale levels, so that the integrated models are used as interpretative tool of experimental data as well as design tool for optimize the performance
Enhanced reactivity of NiO/Pd(100) ultrathin films toward H2: Experimental and theoretical evidence for the role of polar borders
No full textNiO layers in the ultrathin regime exhibit an enhanced reactivity toward hydrogen with respect to the typical chemical inertness of bulk-like thicker samples. Such a behavior has been studied by means of photoemission (from both core and valence band levels) and quantum mechanical calculations. It is found that after H2 dosing in mild conditions (from PH2 = 6.5 × 10-7 Pa and T = 330 K) ultrathin films (thickness ≤6MLE, MLE = monolayer equivalent) quickly react forming metal nickel and water. The kinetic of the reaction has been followed in situ recording the intensity of the O 1s and Ni 2p photoemission spectra under different reaction conditions (PH2 ranging from 5 × 10-7 to 2 × 10-5 Pa and T from 330 up to 453 K), and a first-order dependence of the reaction rate on the PH2 and the activation energy of the rate determining step (0.16 ± 0.02 eV) have been determined. A 8 MLE thick film recovers the behavior of bulk-like NiO(100) surfaces, where more drastic reduction conditions are needed, and the kinetic implies an induction period followed by autocatalysis. The enhanced reactivity has been explained assuming the presence of NiO(100) islands exposing polar borders, whose existence was evidenced by previous scanning tunneling microscopy investigations. Such a scenario is confirmed by ab initio quantum mechanical calculations carried out employing polar and nonpolar terminated stepped surface epitaxially strained in order to account for the presence of the metal support which has not been explicitly included. Reported calculations indicate that the polar border can easily dissociate H2 without any activation barrier. The rate determining step of the reaction has been associated to the stage of the reaction where the previously formed hydroxyl groups react with a second hydrogen molecule (an Eley−Rideal-like mechanism) to form metal Ni islands and water, which readily desorbs
Design of Experiments (DoE): a multivariate approach to dye-sensitized solar cells comprehension and optimization
No full textNowadays, modern science proposes and optimizes new materials and technologies, whose characteristics and performances are governed by many factors. However, the scientific community rarely adopts multivariate strategies for the comprehension of what is proposed. As a striking example, a standard dye-sensitized solar cell (DSSC) is a typical complex system assembled with different and heterogeneous layers (FTO/nanocrystalline semiconductor/sensitizer/electrolyte/Pt-FTO), each one affected by intrinsic variability; moreover the layers influence each other and this increases the number of variables involved at the same time in the photoconversion process. The idea of the present work started from the need to identify all the factors by which the photoconversion processes may be influenced. In order to obtain a significant improvement of photovoltaic performances, particularly in reproducibility, long-term stability and efficiency, a chemometric design of experiments (DoE) approach is here presented for four case studies: the formulation of a UV-cured polymer electrolyte membrane, the composition of a cellulose-based gel-polymer electrolyte, the proper sensitization of a ZnO photoanode and the photostability optimization of a series of NIR dyes under different dipping conditions. We are firmly convinced that this approach will make possible to find the optimal experimental conditions to achieve, within a good reproducibility, optimized performances, both in term of efficiency and long term stabilit
Data-driven tools for the optimization of a pharmaceutical process through its knowledge-driven model
No full textThe use of computationally demanding knowledge-driven models to optimize a process might encounter substantial numerical challenges. Because a model is an abstraction and approximation of the process, calculating the exact model optimum might not be necessary because its industrial implementation is bound to be an approximate one. Here we are exploring an alternative optimization route through a surrogate model. Because one of the decision variables affecting the optimization is time-varying, the Design of Dynamic Experiments is used to estimate the surrogate model. The process considered here is a freeze-drying process widely used in the pharmaceutical industry. The model used is a stochastic model describing the process in great detail. It is shown that the proposed data-driven route calculates the optimum in about 8 h, as opposed to 22 h for the knowledge-driven model, while sacrificing only < 15% in the computed value of the process performance
A general model-based design of experiments approach to achieve practical identifiability of pharmacokinetic and pharmacodynamic models.
No full textThe use of pharmacokinetic (PK) and pharmacodynamic
(PD) models is a common and widespread
practice in the preliminary stages of drug development.
However, PK–PD models may be affected by structural
identifiability issues intrinsically related to their mathematical
formulation. A preliminary structural identifiability
analysis is usually carried out to check if the set of model
parameters can be uniquely determined from experimental
observations under the ideal assumptions of noise-free data
and no model uncertainty. However, even for structurally
identifiable models, real-life experimental conditions and
model uncertainty may strongly affect the practical possibility
to estimate the model parameters in a statistically
sound way. A systematic procedure coupling the numerical
assessment of structural identifiability with advanced
model-based design of experiments formulations is presented
in this paper. The objective is to propose a general
approach to design experiments in an optimal way,
detecting a proper set of experimental settings that ensure
the practical identifiability of PK–PD models. Two simulated
case studies based on in vitro bacterial growth and
killing models are presented to demonstrate the applicability
and generality of the methodology to tackle model
identifiability issues effectively, through the design of
feasible and highly informative experiments
"Le je filmé, scritture del sé nell'audiovisivo: declinazioni e sviluppi teorici nel cinema franco-belga contemporaneo dal 1986 ad oggi
No full textThis research project is devoted to a French and Belgian autobiographical production hardly distributed outside France and Belgium except in single festivals or competitions.
Films have been firstly selected according to a chronological criteria which dating back to 1986, when the first important international conference totally dedicated to autobiographical films took place in Brussell, extends till today. Through the reading of monographic issues devoted to first person films, press releases of thematic festivals consulted in archives and foreign libraries such as the Cinémathèque Française, Centre Pompidou e la Bibliothèque Nationale de France, a first selection of films has been carried out.
After this research only those films in which the director is the main protagonist whether through the use of the voice over or through his/her presence in video. have been taken into account. Where these criteria were not applied, it was a declaration of the author to attest the autobiographical nature of the film.
The aesthetic and formal analysis of the films selected, as well as the recurrence of thematic and expressive features, has allowed the creation of single chapters (Journal filmé, Autobiography/Selfportrait/Autofiction, Subjective documentary, Essay film). Each of them has been introduced by a survey of the main theoretical assumptions at the heart of each subject matter.
This research aims at both providing an overview on English and French studies on subjective cinema and underling those innovative expressive, thematic and aesthetic choices the works analysed reveal.
The first chapter explores the literary studies which starting from the second half of the nineteenth century have fostered a prolific survey on autobiographical works laying the foundations for audiovisual studies on subjective cinema.
The second chapter gives an in-depth view on audiovisual media studies devoted to first person film narrations pointing out the core questions which inspire this specific production.
The third chapter dedicated to those films labelled as video diaries has firstly analysed those literary studies dealing with diary writing in order to find out those features which have been actually recalled or modified in the films analysed. Different kinds of diary films have been sorted out. Through their diversity they overtly testify the hybrid nature of the subjective films we are dealing with.
The fourth chapter has firstly pointed out those phases in the evolution of the documentary film which have deeply influenced the birth of strong subjective documentary productions. The films selected have been analysed adopting a theoretical approach based on Ethnic autobiography; it aims at finding out new possibilities for autobiographical films to be involved in a social, cultural and anthropological survey which could imply a dialogical relation between the subject and the world in which he lives in.
The films included in the fifth chapter embody an experimental space in which documentary, fiction, essay and autobiography, filmed diary and fiction converge into the genre of autofiction, conceived as the post-modern version of autobiography.
The sixth chapter, which deals with the essay form, tries to analyse how the most important philosophical and literary studies dedicated to a definition of the essay contributed to the development of the film essay structure
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