1,038 research outputs found
C ion-implanted TiO2 thin film for photocatalytic applications
Third-generation TiO2 photocatalysts were prepared by implantation of C+ ions into 110 nm thick TiO2 films. An accurate structural investigation was performed by Rutherford backscattering spectrometry, secondary ion mass spectrometry, X-ray diffraction, Raman-luminescence spectroscopy, and UV/VIS optical characterization. The C doping locally modified the TiO2 pure films, lowering the band-gap energy from 3.3 eV to a value of 1.8 eV, making the material sensitive to visible light. The synthesized materials are photocatalytically active in the degradation of organic compounds in water under both UV and visible light irradiation, without the help of any additional thermal treatment. These results increase the understanding of the C-doped titanium dioxide, helpful for future environmental applications. (C) 2015 AIP Publishing LLC
CAOS spectroscopy of Am stars Kepler targets
The {\it Kepler} space mission and its {\it K2} extension provide photometric
time series data with unprecedented accuracy. These data challenge our current
understanding of the metallic-lined A stars (Am stars) for what concerns the
onset of pulsations in their atmospheres. It turns out that the predictions of
current diffusion models do not agree with observations. To understand this
discrepancy, it is of crucial importance to obtain ground-based spectroscopic
observations of Am stars in the {\it Kepler} and {\it K2} fields in order to
determine the best estimates of the stellar parameters.
In this paper, we present a detailed analysis of high-resolution
spectroscopic data for seven stars previously classified as Am stars. We
determine the effective temperatures, surface gravities, projected rotational
velocities, microturbulent velocities and chemical abundances of these stars
using spectral synthesis. These spectra were obtained with {\it CAOS}, a new
instrument recently installed at the observing station of the Catania
Astrophysical Observatory on Mt. Etna. Three stars have already been observed
during quarters Q0-Q17, namely: HD\,180347, HD\,181206, and HD\,185658, while
HD\,43509 was already observed during {\it K2} C0 campaign.
We confirm that HD\,43509 and HD\,180347 are Am stars, while HD 52403,
HD\,50766, HD\,58246, HD\,181206 and HD\,185658 are marginal Am stars. By means
of non-LTE analysis, we derived oxygen abundances from O{\sc
I}7771--5{\AA} triplet and we also discussed the results obtained with
both non-LTE and LTE approaches.Comment: accepted in MNRAS main journal 13 pages, 11 figures, 3 tables. arXiv
admin note: text overlap with arXiv:1404.095
Phenology and Fruit Growth Dynamics of Mango (Mangifera indica L.) in Greenhouse and Open Air in Mediterranean Climate
Phenological evolution of shoots and fruit growth of three mango varietiesâKeitt, Osteen and Tommy Atkinsâwere monitored during two reproductive seasons, from full flowering to fruit harvest on trees cultivated in the open air and inside a greenhouse, in the island of SicilyâItaly. The aim of the study was to assess the behavior of mango trees subjected to summer high temperatures under a permanent plastic cover in the Mediterranean climate. Differences between open air and greenhouse emerged in the dates of first record of major phenological stages and in their duration, and in the fruit growth rates. Greenhouse cultivated trees showed a significant anticipation of flowering and ripening of the fruits respect to open air trees, with harvest conducted earlier during the season. On the other hand, open air cultivated trees achieved fruit maturity in a shorter time compared to the greenhouse, with fruits needing between 90 and 110 days after full flowering to reach their final dimensionsâwhile the trees in the greenhouse needed at least 125 days. The study allowed to understand the growth dynamics of mango fruits subjected to extreme high temperatures and provides new information to evaluate the opportunity of greenhouse cultivation of mango in the Mediterranean climate
Structure effects on reaction mechanisms in collisions induced by halo and weakly bound nuclei around the Coulomb barrier
The study of reaction mechanisms in collisions induced by halo and/or weakly bound nuclei around the Coulomb barrier has recently been the subject of many theoretical and experimental papers. Here we discuss our present understanding of some aspects of such a topic by briefly summarizing experimental data obtained by different authors with particular attention to some results obtained in the last years by our collaboration
Modified Atmosphere Packaging and low temperature storage extend marketability of cherimoya (Annona cherimola Mill.)
Cherimoya is a subtropical fruit characterized by a delicious, sweet flavor and beneficial health properties, which found suitable growing conditions in the South of Italy. However, the marketing of this product is halted by its high perishability, which limits the shelf-life of the fresh fruit to few days after harvest and does not allow for commercialization beyond local markets. Studies have shown that storage of this fruit in controlled atmosphere, using Modified Atmosphere Packaging technologies, extended the post-harvest life of Cherimoya, but little is still known about the evolution of its sensory, nutraceutical and microbiological characteristics during such storage period. In this paper, we studied the effect of a 4-days long active-MAP (30% CO2 â 10% O2 â 60% N2) storage period, associated with cold temperatures, on the physico-chemical, sensory, nutraceutical and microbiological quality traits of Italian-grown cherimoya fruits, compared with passive-MAP (Air composition, 21% O2 + 1% CO2 + 78% N2) and simple cold storage. Active-MAP proved effective in delaying the reaching of the optimal consumption point until 10 days from harvest, besides showing absence of microbial growth until after 7 days from harvest. Both active- and passive-MAP treatments maintained better nutraceutical values than control until the end of the trial period, and sensory analysis confirmed that active-MAP treated fruits were at the optimal commercial stage after 10 days from harvest
First optical validation of a Schwarzschild Couder telescope: the ASTRI SST-2M Cherenkov telescope
The Cherenkov Telescope Array (CTA) represents the most advanced facility
designed for Cherenkov Astronomy. ASTRI SST-2M has been developed as a
demonstrator for the Small Size Telescope in the context of the upcoming CTA.
Its main innovation consists in the optical layout which implements the
Schwarzschild-Couder configuration and is fully validated for the first time.
The ASTRI SST-2M optical system represents the first qualified example for two
mirrors telescope for Cherenkov Astronomy.
This configuration permits to (i) maintain a high optical quality across a
large FoV (ii) de-magnify the plate scale, (iii) exploit new technological
solutions for focal plane sensors. The goal of the paper is to present the
optical qualification of the ASTRI SST-2M telescope. The qualification has been
obtained measuring the PSF sizes generated in the focal plane at various
distance from the optical axis. These values have been compared with the
performances expected by design.
After an introduction on the Gamma Astronomy from the ground, the optical
design and how it has been implemented for ASTRI SST-2M is discussed. Moreover
the description of the setup used to qualify the telescope over the full field
of view is shown.
We report the results of the first--light optical qualification. The required
specification of a flat PSF of arcmin in a large field of view ~10
deg has been demonstrated. These results validate the design specifications,
opening a new scenario for Cherenkov Gamma ray Astronomy and, in particular,
for the detection of high energy (5 - 300 TeV) gamma rays and wide-field
observations with CTA.Comment: 6 pages, 5 figure
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Flexible and conformable strain gauges for smart pressure sensors systems: Static and dynamic characterization
An innovative segment of the semiconductor and electronics industry in the last years is driven by new sensors embedded in smart devices and systems with thin form factor, connected to existing infrastructures via standard communication interfaces. The increased maturity of industrial sensor technologies and associated readout electronics enabled new products penetrating multiple market sectors. Among the different classes of smart sensing systems that can be realized with thin and truly flexible form factor, thin film strain gauges are ideally suited for the implementation of pressure sensing membranes. In this work we will focus on the development of static and dynamic testing methods of a strain gauge module whose applications are intended as a flexible and conformable strain/pressure sensor, adaptable for wireless communications
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