130,470 research outputs found
DW Cancri in X-rays
No full textWe report on the XMM-Newton observation of DW Cnc, a candidate intermediate polar candidate whose historical optical light curve shows the existence of periods at ≃38, ≃86, and ≃69 min, which were interpreted as the white dwarf spin, the orbital and the spin-orbit beat periodicities. By studying the 0.3-10 keV light curves, we confirm the existence of a period at ≃ 38 min and find in the OM light curve a signature for a period at 75 ± 21 min, which is consistent with both the orbital and spin-orbit beat. These findings allow us to unveil without any doubt, the nature of DW Cnc as an accreting intermediate polar. The EPIC and RGS source spectra were analysed and a best-fitting model, consisting of a multitemperature plasma, was found. The maximum temperature found when fitting the data is kTmax ≃ 31 keV, which can be interpreted as an upper limit to the temperature of the shock
ASTRONET: planetary observations in remote collaborative web environment
No full textIn this paper we discuss the objectives, the key technical aspects and the main
results of AstroNet, a Web-controlled telescope that can be simultaneously operated by
small groups of users (2-20 in turn), like in a real astronomical observatory. AstroNet is
the outcome of a collaboration between the Astrophysics group and the DIDA-Lab of the
University of Salento and has been developed to respond to the increasing number of re-
quests coming from schools and families about astronomy lectures and sky observation
tutorials. In the last year, AstroNet permitted to about 1000 young students to perform rich
observation experiences from both school and home, with the same global effort previously
needed to offer a similar experience to about 100 people.
The recognition and the analysis of the main lunar geologic structures, the monitoring of
the complex and diversified Jupiter atmosphere, the evolution of comets in proximity of
perihelion are only some of the possible targets of observations and imaging sessions that
are suitable to a great number of thorough analyses. Moreover, with the same instrumental
equipment, even if with a more well-constructed approach, it is possible to start low cost
scientific research projects in the field of asteroid photometry, variable stars or extrasolar
planet transits
Infrared spectroscopy of carbonate samples of biotic origin relevant to Mars exobiological studies
No full textBecause it is possible that Mars experienced an ancient climate warmer and wetter than the present one, it is reasonable to suppose that simple
forms of life developed there, in the underground or at the surface, as in the terrestrial primitive biosphere. In this work we have performed
infrared (IR) transmission spectroscopic analyses directed to examine the reaction to heat treatments of biotic (fresh and fossil materials) and
abiotic particulate samples composed of calcium carbonate (aragonite or calcite). The aim is to check if IR spectroscopy can be a useful tool for
discriminating between abiotic and biotic (fossil) carbonate samples collected on the martian surface, during in situ or sample-return missions.
An important result we found is that, after thermal processing, it is possible to distinguish, by means of IR spectroscopy, abiotic aragonite from
aragonite of recent biological origin. In addition we have found that the spectral behaviour of all the analysed fossil samples after heat treatment
is the same as that of fresh biotic material irrespective of the original structure (whether aragonite or calcite)
Water Protection Information Management by Syntactic and Semantic Interoperability of Heterogeneous Repositories
No full textImproving wood resistance to decay by nanostructured ZnO-based treatments
No full textIn this study, the maple wood surface was coated with nanostructured zinc oxide, grown on the surface by using a hydrothermal process, and furtherly treated with shellac varnish. Samples obtained both after ZnO treatment and after the final varnish application were characterized by different techniques, i.e., X-ray diffraction (XRD), scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDS), micro-FTIR with attenuated total reflectance (μ-ATR-FTIR), chromatic variation measurements, and contact angle determinations. Analytical results showed that the wood surface was covered by quite a homogeneous array of inorganic nanoparticles and that the natural resin forms a regular film over the ZnO nanostructures. An accelerated aging test was used to evaluate the protecting effectiveness of the treatments towards UV-induced decay of wood material. After the test, wood treated with ZnO and with the shellac/ZnO combination underwent a considerably lower chromatic change if compared to the untreated wood, suggesting an enhanced resistance of the treated maple to the decay due to light exposition. The presence of nanostructured ZnO protects from decay not only the wood substrate but also the shellac film. A microbiology test showed that growth of fungal species, e.g., common mold, is prevented on the wood surface treated with ZnO or with shellac/ZnO, indicating that the nanostructured zinc oxide also provides an effective protection from biodeterioration. The coating obtained by consecutive application of nanosized ZnO particles and shellac varnish combines the excellent aesthetical features and water repellence of the traditional finish with the protecting effectiveness of the nanostructured inorganic component
PRIMA SEGNALAZIONE IN ITALIA DI ARCTODIAPTOMUS KERKYRENSIS (CRUSTACEA COPEPODA CALANOIDA)
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