Search results for "14"

Measuring optical anisotropy in poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) films with added graphene

2015

Abstract Graphene is a 2D nanomaterial having a great potential for applications in electronics and optoelectronics. Composites of graphene with conducting polymers have shown high performance in practical devices and their solution-processability enables low-cost and high-throughput mass manufacturing using printing techniques. Here we measure the effect of incorporation of graphene into poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) to the optical anisotropy, absorbance and conductivity of the film. Uniaxial anisotropy in PEDOT:PSS films has been thought to be caused by the spin-coating process used in fabrication. We have characterized spray- and spin-coated films …

Characterization of Supersonic Gas Jets for High-Resolution Laser Ionization Spectroscopy of Heavy Elements

2018

© 2018 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. The method of laser spectroscopy in supersonic gas jets was proposed for high-resolution and high-efficiency in-gas laser ionization and spectroscopy studies of short-lived nuclei. The flow properties of such supersonic gas jets have been characterized under off-line conditions. Planar laser-induced fluorescence spectroscopy of s…

The NUMEN project @ LNS: Status and perspectives

2017

The NUMEN project aims at accessing experimentally driven information on Nuclear Matrix Elements (NME) involved in the half-life of the neutrinoless double beta decay (0νββ), by high-accuracy measurements of Heavy Ion (HI) induced Double Charge Exchange (DCE) reaction cross sections. In particular, the (18O,18Ne) and (20Ne,20O) reactions are used as tools for β+β+ and β−β− decays, respectively. In the experiments, performed at INFN - Laboratory Nazionali del Sud (LNS) in Catania, the beams are accelerated by the Superconducting Cyclotron (CS) and the reaction ejectiles are detected the MAGNEX magnetic spectrometer. The measured cross sections are challengingly low (a few nb), being the tota…

Three-dimensional skyrmions in spin-2 Bose–Einstein condensates

2017

We introduce topologically stable three-dimensional skyrmions in the cyclic and biaxial nematic phases of a spin-2 Bose-Einstein condensate. These skyrmions exhibit exceptionally high mapping degrees resulting from the versatile symmetries of the corresponding order parameters. We show how these structures can be created in existing experimental setups and study their temporal evolution and lifetime by numerically solving the three-dimensional Gross-Pitaevskii equations for realistic parameter values. Although the biaxial nematic and cyclic phases are observed to be unstable against transition towards the ferromagnetic phase, their lifetimes are long enough for the skyrmions to be imprinted…

An Examination of Tourist Arrivals Dynamics Using Short-Term Time Series Data: A Space—Time Cluster Approach

2013

The purpose of this study is to examine the development of Italian tourist areas ( circoscrizioni turistiche) through a cluster analysis of short time series. The technique is an adaptation of the functional data analysis approach developed by Abraham et al (2003), which combines spline interpolation with k-means clustering. The findings indicate the presence of two patterns (increasing and stable) averagely characterizing groups of territories. Moreover, tests of spatial contiguity suggest the presence of ‘space–time clusters’; that is, areas in the same ‘time cluster’ are also spatially contiguous. These findings appear to be more robust in particular for those series characterized by an…

Responsabilité sociale des organisations sportives professionnelles.

2011

Quando i recinti tracimeranno. Lo sprawl e le insulae dello ZEN 2

2008

Dal 1989 mi interesso al quartiere ZEN di Palermo, al quale ho dedicato la tesi di dottorato, alcuni articoli, una monografia, molte lezioni, diversi progetti e, ovviamente, moltissimi sopralluoghi. Sono trascorsi, quindi, circa venti anni dalla fase iniziale di studio e ho avuto modo, in questo periodo, di seguire quelle trasformazioni che, insieme al quartiere, hanno riguardato l’area più a nord della Piana dei Colli. Punti di vista privilegiati per seguire e comprendere tali mutamenti sono il Monte Pellegrino e la strada panoramica che, almeno per una parte, si srotola, come un nastro, lungo il fianco che limita ad est il parco de La Favorita. Da molti degli sguardi offerti dal monte, c…

Stochastic gravito-inertial modes discovered by CoRoT in the hot Be star HD 51452

2012

International audience; Context. Be stars are rapidly rotating stars with a circumstellar decretion disk. They usually undergo pressure and/or gravity pulsation modes excited by the κ-mechanism, i.e. an effect of the opacity of iron-peak elements in the envelope of the star. In the Milky Way, p-modes are observed in stars that are hotter than or equal to the B3 spectral type, while g-modes are observed at the B2 spectral type and cooler. Aims. We observed a B0IVe star, HD 51452, with the high-precision, high-cadence photometric CoRoT satellite and high-resolution, ground-based HARPS and SOPHIE spectrographs to study its pulsations in great detail. We also used the lower resolution spectra a…

The Gaia-ESO Survey: impact of extra mixing on C and N abundances of giant stars

2018

The GES survey using FLAMES at the VLT has obtained high-resolution UVES spectra for a large number of giant stars, allowing a determination of the abundances of the key chemical elements C and N at their surface. The surface abundances of these chemical species are well-known to change in stars during their evolution on the red giant branch after the first dredge-up episod, as a result of extra-mixing phenomena. We investigate the effects of thermohaline mixing on C and N abundances using the first comparison between the GES [C/N] determinations with simulations of the observed fields using a model of stellar population synthesis. We explore the effects of thermohaline mixing on the chemic…

Senza ISSN

2012

Con questo scritto Andrea Sciascia chiarisce, secondo il suo punto di vista, quali siano le ragioni che hanno dato vita all’e-journal, diretto da Marcello Panzarella. Il riflettere su queste cause è l’occasione per fare il punto della situazione sugli effetti della riforma universitaria in Italia e, nello specifico, nell’Ateneo di Palermo. I successivi accorpamenti e la conseguente scomparsa delle facoltà costruiscono un quadro inedito che presenta anche dei lati oscuri, soprattutto per quelle facoltà numericamente più esigue, come quella di Architettura. All’interno di questo scenario, la riflessione si sposta sulle peculiarità della Facoltà di Architettura di Palermo e sul rischio che le …