Synthesis and characterization of nanocomposites of thermoplastic polyurethane with both graphene and graphene nanoribbon fillers

Thermoplastic polyurethane (TPU) nanocomposites containing graphene and graphene nanoribbons were obtained by polymerizing 1,4-butanediol with two diisocyanates (namely, 1,6-hexane diisocyanate or isophorone diisocyanate), in which the nanofillers were previously dispersed. Raman spectroscopy and Transmission Electron Microscopy demonstrated the formation of few-layer graphene and graphene nanoribbons dispersed in the monomers. At variance to the methods commonly reported in literature, that used in this work consists of the direct exfoliation of graphite without any chemical manipulation. Apart from the obvious cost and ease advantages, the so-obtained graphene does not contain any carboxy or alkoxy groups formed during the exfoliation process, which, at variance, are typically present in the most commonly reported methods. This finding paves the way toward the large-scale production of graphene and its nanoribbons, which are considered even more interesting than graphene itself for many potential applications. The obtained nanocomposites show a peculiar thermal and rheological behavior due to the presence of the nanofillers and to their reinforcing or plasticizing effect exerted on the TPU matrices.     

Shot scale distribution in art films

The scale of shot, i.e. the apparent distance of the camera from the main subject of a scene, is one of the main stylistic and narrative functions of audiovisual products, conveying meaning and inducing the viewer’s emotional state. The statistical distribution of different shot scales in a film may be an important identifier of an individual film, an individual author, and of various narrative and affective functions of a film. In order to understand at which level shot scale distribution (SSD) of a movie might become its fingerprint, it is necessary to produce automatic recognition of shot scale on a large movie corpus. In our work we propose an automatic framework for estimating the SSD of a movie by using inherent characteristics of shots containing information about camera distance, without the need to recover the 3D structure of the scene. In the experimental investigation, the comparison of obtained results with manual SSD annotations proves the validity of the framework. Experiments conducted on movies by Michelangelo Antonioni taken from different stylistic periods (1950–57, 1960–64, 1966–75, 1980–82) show a strong similarity in shot scale distributions within each period, thus opening interesting research lines regarding the possible aesthetic and cognitive sources of such a regularity.     

Deposition of Pt nanoparticles on different carbonaceous materials by using different preparation methods for PEMFC electrocatalysts

The objective of this study is to evaluate different methods to obtain Pt (20 wt%)/carbon electrocatalysts, in order to identify the conditions that lead to electrocatalysts with the best electrochemical performance. This paper involves the study of different methods for the deposition and reduction of H₂PtCl₆ on three carbon supports: Vulcan carbon, Multiwall carbon nanotubes and mesoporous carbons. The deposition–reduction methods in liquid phase were carried out with HCOOH or NaBH₄ as reducing agents. Besides, the conventional impregnation was carried out by deposition of H₂PtCl₆ on carbon followed by a reduction with H₂ at high temperature. The electrochemical performance of supported Pt catalysts prepared by reduction in liquid phase is strongly dependent on the metallic dispersion, the particle size distribution and the nature of the carbonaceous material used as a support. Results show that the deposition–reduction method using HCOOH 0.3 M at 50–60 °C and a mesoporous carbon leads to the most efficient electrocatalyst.     

Control of attendance applied in higher education through mobile NFC technologies

This paper presents an improved attendance control system, required for continuous evaluation which has become compulsory following the Bologna Process. It provides a solution based on NFC technology and is based on a real project developed and pilot tested at the “Universidad Pontificia de Salamanca, Campus Madrid”.     

Large-scale parallel lattice Boltzmann–cellular automaton model of two-dimensional dendritic growth

An extremely scalable lattice Boltzmann (LB)–cellular automaton (CA) model for simulations of two-dimensional (2D) dendritic solidification under forced convection is presented. The model incorporates effects of phase change, solute diffusion, melt convection, and heat transport. The LB model represents the diffusion, convection, and heat transfer phenomena. The dendrite growth is driven by a difference between actual and equilibrium liquid composition at the solid–liquid interface. The CA technique is deployed to track the new interface cells. The computer program was parallelized using the Message Passing Interface (MPI) technique. Parallel scaling of the algorithm was studied and major scalability bottlenecks were identified. Efficiency loss attributable to the high memory bandwidth requirement of the algorithm was observed when using multiple cores per processor. Parallel writing of the output variables of interest was implemented in the binary Hierarchical Data Format 5 (HDF5) to improve the output performance, and to simplify visualization. Calculations were carried out in single precision arithmetic without significant loss in accuracy, resulting in 50% reduction of memory and computational time requirements. The presented solidification model shows a very good scalability up to centimeter size domains, including more than ten million of dendrites.     

Hand pose aware multimodal isolated sign language recognition

Multimedia Tools and Applications - Isolated hand sign language recognition from video is a challenging research area in computer vision. Some of the most important challenges in this area include...     

Portfolio Selection Using Multivariate Semiparametric Estimators and a Copula PCA-Based Approach

Computational Economics - This paper investigates the implications for portfolio theory of using multivariate semiparametric estimators and a copula-based approach, especially when the number of...     

Other than detecting impact in advance,alternative metrics could act as early warning signs of retractions: tentative findings of a study into the papers retracted by PLoS ONE

Scientometrics - The so-called altmetrics—short for alternative metrics—have gained their place in the scholarly publishing landscape, especially providing article-level complementary...