A five-wave HLL Riemann solver for relativistic MHD

We present a five-wave Riemann solver for the equations of ideal relativistic magnetohydrodynamics. Our solver can be regarded as a relativistic extension of the five-wave HLLD Riemann solver initially developed by Miyoshi and Kusano for the equations of ideal MHD. The solution to the Riemann problem is approximated by a five wave pattern, comprised of two outermost fast shocks, two rotational discontinuities and a contact surface in the middle. The proposed scheme is considerably more elaborate than in the classical case since the normal velocity is no longer constant across the rotational modes. Still, proper closure to the Rankine-Hugoniot jump conditions can be attained by solving a nonlinear scalar equation in the total pressure variable which, for the chosen configuration, has to be constant over the whole Riemann fan. The accuracy of the new Riemann solver is validated against one dimensional tests and multidimensional applications. It is shown that our new solver considerably improves over the popular HLL solver or the recently proposed HLLC schemes.Comment: 15 pages, 19 figures. Accepted for Publication in MNRA

TT 31 OF KHONSU AT SHEIK ABD EL-GURNAH (THEBES): RESEARCHES INTO CONSTRUCTED LANDSCAPES

The Theban tomb (TT) 31 of Khonsu, First Prophet of Menkheperre, is an ideal casestudy to understand the perception of natural and constructed landscapes, throughout the analysis of their different iconographies. Starting from the description of the decorative programme of Khonsu’s tomb, it could be possible to identify elements of continuity and differences between the depictions of the different sacred structures that can be appreciated also within the Theban and Amarnian tombs of the nobles during the XVIII and XIX Dynasty. The use of specific themes and iconographies might correspond to peculiar conceptions of the most sacred space, the temple

Erratum: Progenitor-explosion connection and remnant birth masses for neutrino-driven supernovae of iron-core progenitors (2012, ApJ, 757, 69)

An erroneous interpretation of the hydrodynamical results led to an incorrect determination of the fallback masses in Ugliano et al. (2012), which also (on a smaller level) affects the neutron star masses provided in that paper. This problem was already addressed and corrected in the follow-up works by Ertl et al. (2015) and Sukhbold et al. (2015). Therefore, the reader is advised to use the new data of the latter two publications. In the remaining text of this Erratum we present the differences of the old and new fallback results in detail and explain the origin of the mistake in the original analysis by Ugliano et al. (2012).Comment: 3 pages, 2 figures; submitted to The Astrophysical Journa

A two-parameter criterion for classifying the explodability of massive stars by the neutrino-driven mechanism

Thus far, judging the fate of a massive star (either a neutron star (NS) or a black hole) solely by its structure prior to core collapse has been ambiguous. Our work and previous attempts find a non-monotonic variation of successful and failed supernovae with zero-age main-sequence mass, for which no single structural parameter can serve as a good predictive measure. However, we identify two parameters computed from the pre-collapse structure of the progenitor, which in combination allow for a clear separation of exploding and non-exploding cases with only few exceptions (~1-2.5%) in our set of 621 investigated stellar models. One parameter is M4, defining the normalized enclosed mass for a dimensionless entropy per nucleon of s=4, and the other is mu4 = d(m/M_sun)/d(r/1000 km) at s=4, being the normalized mass-derivative at this location. The two parameters mu4 and M4*mu4 can be directly linked to the mass-infall rate, Mdot, of the collapsing star and the electron-type neutrino luminosity of the accreting proto-NS, L_nue ~ M_ns*Mdot, which play a crucial role in the "critical luminosity" concept for the theoretical description of neutrino-driven explosions as runaway phenomenon of the stalled accretion shock. All models were evolved employing the approach of Ugliano et al. for simulating neutrino-driven explosions in spherical symmetry. The neutrino emission of the accretion layer is approximated by a gray transport solver, while the uncertain neutrino emission of the 1.1 M_sun proto-NS core is parametrized by an analytic model. The free parameters connected to the core-boundary prescription are calibrated to reproduce the observables of Supernova 1987A for five different progenitor models.Comment: 23 pages, 12 figures; accepted by ApJ; revised version considerably enlarged (Fig. 7 and Sect.3.6 added

Applicazione delle logiche di asservimento kanban nel reparto montaggio. Il caso Euroventilatori Srl

Il seguente elaborato è frutto della mia esperienza di tirocinio svolta presso Sintesia Srl, società di consulenza organizzativa che supporta i clienti nella trasformazione lean dei processi operativi. Il progetto nasce dalla collaborazione con uno dei loro clienti Euroventilatori International Srl, leader nel campo della progettazione, realizzazione e distribuzione di ventilatori industriali.ope

Automatically Detecting Changes and Anomalies in Unmanned Aerial Vehicle Images

The use of unmanned aerial vehicles (UAVs) in civil aviation is growing up quickly, enabling new scenarios, especially in environmental monitoring and public surveillance services. So far, Earth observation has been carried out only through satellite images, which are limited in resolution and suffer from important barriers such as cloud occlusion. Microdrone solutions, providing video streaming capabilities, are already available on the marketplace, but they are limited to altitudes of a few hundred feet. In contrast, UAVs equipped with high quality cameras can fly at altitudes of a few thousand feet and can fill the gap between satellite observations and ground sensors. Therefore, new needs for data processing arise, spanning from computer vision algorithms to sensor and mission management. This paper presents a solution for automatically detecting changes in images acquired at different times by patrolling UAVs flying over the same targets (but not necessarily along the same path or at the same altitude). Change detection in multi-temporal images is a prerequisite for land cover inspection, which, in turn, sets up the basis for detecting potentially dangerous or threatening situations

trans-Resveratrol, Quercetin, (+)-Catechin, and (-)-Epicatechin Content in South Italian Monovarietal Wines: Relantionship with Maceration Time and Marc Pressing during Winemaking

The concentrations of trans-resveratrol, (+)-catechin, (-)-epicatechin, and quercetin were evaluated by means of high-performance liquid chromatography-diode array detection in red wines obtained from Aglianico, Piedirosso, and Nerello Mascalese grapes. The trans-resveratrol and epicatechin concentrations did not differ significantly between experimental wines. The concentration of quercetin in Nerello Mascalese wines was more than twice that observed in Aglianico and Piedirosso wines. Nerello Mascalese wines also significantly differed from other wines in the (+)-catechin content, which was significantly higher than those found in the other two wines. During maceration, the maximum extraction of trans-resveratrol was reached after 12 days for Aglianico and Piedirosso, after which a decline was observed. On the contrary, in the case of Nerello Mascalese, the concentration of trans-resveratrol increased steadily throughout the whole maceration process. After 2 days of maceration, the maximum concentration of quercetin was observed in Aglianico must, whereas the maximum quercetin extraction was reached after 12 days for Piedirosso and 17 days for Nerello Mascalese. The maximum levels of (+)-catechin and (-)-epicatechin were generally observed after 12 days of maceration for all wines, although a decline of (-)-epicatechin occurred after maximum extraction in Aglianico and Piedirosso wines. Following marc pressing, a significant increase in the concentration of trans-resveratrol for Aglianico, (+)-catechin and (-)-epicatechin for Piedirosso, and (-)-epicatechin for Nerello Mascalese was observed

Screening of Hanseniaspora Strains for the Production of Enzymes with Potential Interest for Winemaking

Some non-Saccharomyces yeasts, including Hanseniaspora, participate in the first stages of wine fermentation. Besides their importance in the wine production process some of these yeasts have been described to be potential producers of hydrolytic enzymes to industrial level. In this work, we pretend to evaluate the technological abilities of the Hanseniaspora strains deposited in the Spanish Type Culture Collection (CECT). First of all, we considered verification of the correct identification of the strains using several miniaturized biochemical systems and molecular techniques (PCR, RFLP and sequencing of the ribosomal D1/D2 region). The results allowed us to verify the correct adscription of the 26 strains included in this study, which exhibited concordant profiles of restriction with one of the three species described in previous studies (H. occidentalis, H. osmophila and H. valbyensis). Some other strains assigned to the species (H. uvarum, H. vineae and H. guilliermondii) showed at least two different profiles. The other objective of this study was to perform an initial screening to characterize both at quantitative and qualitative levels, the ability of these yeasts to produce valuable enzymes for wine fermentation (increase of aroma) and other applications. The more important enzymatic activities detected were β-glucosidase, β-xylosidase, and protease. The HU7, HU8, HV1, HV3, HO2 and HOC1 strains showed high levels of β-glucosidase and β-xylosidase activity, whereas some strains (HG1, HG3, HVA1, HOC 3 and HOC4 were useful for protease productio

Occurrence, biogenesis and sensory impact of methyl salicylate in Lugana wines

Lugana wines are produced in the winemaking regions of Veneto and Lombardia, employing Turbiana grapes grown in the proximity of the Garda Lake. Methyl salicylate (MeSA) has been reported as a potentially impactful compound in Lugana wines. The aim of this study was to evaluate the occurrence of MeSA in commercial Lugana wines, elucidate its formation during winemaking and aging, and assess its potential contribution to Lugana aroma. MeSA was quantified in a total of 93 samples including Lugana, Verdicchio (another Italian white wine produced in central Italy using Turbiana grapes locally referred to as Verdicchio), as well as other Italian white and red wines such as Corvina, Corvinone, Garganega, Sangiovese, Pinot nero, Pinot grigio. The results showed that Lugana showed an average concentration of MeSA of 50.6 µg/L, Verdicchio of 33.4 µg/L, while the rest of the wines showed concentration below 5 µg/L. These results indicate that MeSA can be considered a varietal marker of Lugana wines, as well as more in general of wines obtained from the Turbiana/Verdicchio varietal cluster. Concentration of free MeSA in Lugana grape must is however low, and experimental fermentations showed that MeSA was largely formed by yeast activity during alcoholic fermentation, which hydrolyzes the glycosidic precursors of MeSA present in the must to release the aglycone. Additional MeSA can be formed in wine during aging by acid hydrolysis of the glycosidic precursors. Finally, the olfactory threshold of MeSA in a commercial Lugana was estimated by BET method at 38 µg/L, suggesting that MeSA could play a role in Lugana aroma