Mechanical behaviour with temperatures of aluminum matrix composites with CNTs

Aluminum is a very useful structural metal employed in different industrial sectors, in particular it is used in large quantities in automotive, aeronautic and nautical industries. The main reasons of its wide use are: a very good oxidation resistance, excellent ductility, low melting temperature (660 °C) and low density (2.71 g/cm3). However, in order to reduce the emissions and fuel consumption is necessary to reduce the overall weight of vehicles by increasing mechanical properties of the structural material. The improvement of mechanical properties is normally achieved through use of reinforcement in materials, used like matrix, in order to improve some specific characteristics. In this work composites of carbon nanotubes (CNTs) dispersed in aluminum were made. The most difficulties in the preparation of this type of composite are represented by the low wettability between metallic matrix and fillers and the possibility of the oxidation of metal during melting with consequent decreasing of mechanical proprieties. The composite was obtained by three consecutive step: the first one is the functionalization of fillers surface to improve the fillers dispersion, the second one is the dispersion of fillers in the matrix by powder mixing and the third one is the melting and casting of the mix prepared. In particular, fillers used are multi walled carbon nanotubes (MWCNTs) with functionalized surface by treatment with a solfonitric solution. Melting and casting are carried out with the aid of an induction furnace with a controlled atmosphere system and centrifugal casting. Argon is the inert gas used to prevent the oxidation of aluminium during fusion. Young’s modulus was evaluated at different temperature and correlated with the different CNTs percentage. The dispersion rate of fillers and the microstructure of the sample were evaluated by FESEM micrograph

Saturn as a radio source

Magnetospheric radio emissions, Saturn electrostatic discharges, inferred source locations, and emission theories are addressed

Heat capacity, configurational heat capacity and fragility of hydrous magmas

International audienceThe glassy and liquid heat capacities of four series of dry and hydrous natural glasses and magma as a function of temperature and water content (up to 19.9 mol%) were investigated using differential scanning calorimetry (DSC). The analyzed compositions are basalt, latite, trachyte and pantellerite. The results of this study indicate that the measured heat capacity of glasses (Cpg) is a linear function of composition and is well reproduced by the empirical model of Richet (1987). For the investigated glasses, the partial molar heat capacity of water can be considered as independent of composition, in agreement with Bouhifd et al. (2006). For hydrous liquids, the heat capacity (Cpliq) decreases nonlinearly with increasing water content. Previously published models, combined with the partial molar heat capacity of water from the literature, are not able to reproduce our experimental data in a satisfactory way. We estimated the partial molar heat capacity of water (CpH2O) in hydrous magma over a broad compositional range. The proposed value is 41 ± 3 J mol-1 K-1. Water strongly affects the configurational heat capacity at the glass transition temperature [Cpconf (Tg)]. An increases of Cpconf (Tg) with water content was measured for the polymerized liquids (trachyte and pantellerite), while the opposite behavior was observed for the most depolymerized liquids (basalt and latite). Structural and rheological implications of this behavior are discussed in light of the presented results

Text-based Editing of Talking-head Video

Editing talking-head video to change the speech content or to remove filler words is challenging. We propose a novel method to edit talking-head video based on its transcript to produce a realistic output video in which the dialogue of the speaker has been modified, while maintaining a seamless audio-visual flow (i.e. no jump cuts). Our method automatically annotates an input talking-head video with phonemes, visemes, 3D face pose and geometry, reflectance, expression and scene illumination per frame. To edit a video, the user has to only edit the transcript, and an optimization strategy then chooses segments of the input corpus as base material. The annotated parameters corresponding to the selected segments are seamlessly stitched together and used to produce an intermediate video representation in which the lower half of the face is rendered with a parametric face model. Finally, a recurrent video generation network transforms this representation to a photorealistic video that matches the edited transcript. We demonstrate a large variety of edits, such as the addition, removal, and alteration of words, as well as convincing language translation and full sentence synthesis

On the usefulness of finding charts Or the runaway carbon stars of the Blanco & McCarthy field 37

We have been recently faced with the problem of cross--identifying stars recorded in historical catalogues with those extracted from recent fully digitized surveys (such as DENIS and 2MASS). Positions mentioned in the old catalogues are frequently of poor precision, but are generally accompanied by finding charts where the interesting objects are flagged. Those finding charts are sometimes our only link with the accumulated knowledge of past literature. While checking the identification of some of these objects in several catalogues, we had the surprise to discover a number of discrepancies in recent works.The main reason for these discrepancies was generally the blind application of the smallest difference in position as the criterion to identify sources from one historical catalogue to those in more recent surveys. In this paper we give examples of such misidentifications, and show how we were able to find and correct them.We present modern procedures to discover and solve cross--identification problems, such as loading digitized images of the sky through the Aladin service at CDS, and overlaying entries from historical catalogues and modern surveys. We conclude that the use of good finding charts still remains the ultimate (though time--consuming) tool to ascertain cross--identifications in difficult cases.Comment: 4 pages, 1 figure, accepted by A&

New Analysis of Mercury Laser Altimeter Crossovers to Improve Geodetic Constraints by MESSENGER

No abstract availabl

Global gene expression analysis provides insight into local adaptation to geothermal streams in tadpoles of the Andean toad Rhinella spinulosa

Indexación: Web of Science; Scopus.The anuran Rhinella spinulosa is distributed along the Andes Range at altitudes that undergo wide daily and seasonal variation in temperature. One of the populations inhabits geothermal streams, a stable environment that influences life history traits such as the timing of metamorphosis. To investigate whether this population has undergone local adaptation to this unique habitat, we carried out transcriptome analyses in animals from two localities in two developmental stages (prometamorphic and metamorphic) and exposed them to two temperatures (20 and 25 degrees C). RNA-Seq, de novo assembly and annotation defined a transcriptome revealing 194,469 high quality SNPs, with 1,507 genes under positive selection. Comparisons among the experimental conditions yielded 1,593 differentially expressed genes. A bioinformatics search for candidates revealed a total of 70 genes that are highly likely to be implicated in the adaptive response of the population living in a stable environment, compared to those living in an environment with variable temperatures. Most importantly, the population inhabiting the geothermal environment showed decreased transcriptional plasticity and reduced genetic variation compared to its counterpart from the non-stable environment. This analysis will help to advance the understanding of the molecular mechanisms that account for the local adaptation to geothermal streams in anurans.https://www.nature.com/articles/s41598-017-01982-

Hierarchical progressive surveys. Multi-resolution HEALPix data structures for astronomical images, catalogues, and 3-dimensional data cubes

Scientific exploitation of the ever increasing volumes of astronomical data requires efficient and practical methods for data access, visualisation, and analysis. Hierarchical sky tessellation techniques enable a multi-resolution approach to organising data on angular scales from the full sky down to the individual image pixels. Aims. We aim to show that the Hierarchical progressive survey (HiPS) scheme for describing astronomical images, source catalogues, and three-dimensional data cubes is a practical solution to managing large volumes of heterogeneous data and that it enables a new level of scientific interoperability across large collections of data of these different data types. Methods. HiPS uses the HEALPix tessellation of the sphere to define a hierarchical tile and pixel structure to describe and organise astronomical data. HiPS is designed to conserve the scientific properties of the data alongside both visualisation considerations and emphasis on the ease of implementation. We describe the development of HiPS to manage a large number of diverse image surveys, as well as the extension of hierarchical image systems to cube and catalogue data. We demonstrate the interoperability of HiPS and Multi-Order Coverage (MOC) maps and highlight the HiPS mechanism to provide links to the original data. Results. Hierarchical progressive surveys have been generated by various data centres and groups for ~200 data collections including many wide area sky surveys, and archives of pointed observations. These can be accessed and visualised in Aladin, Aladin Lite, and other applications. HiPS provides a basis for further innovations in the use of hierarchical data structures to facilitate the description and statistical analysis of large astronomical data sets.Comment: 21 pages, 6 figures. Accepted for publication in Astronomy & Astrophysic

Detailed study of the microwave emission of the supernova remnant 3C 396

We have observed the supernova remnant 3C~396 in the microwave region using the Parkes 64-m telescope. Observations have been made at 8.4 GHz, 13.5 GHz, and 18.6 GHz and in polarisation at 21.5 GHz. We have used data from several other observatories, including previously unpublished observations performed by the Green Bank Telescope at 31.2 GHz, to investigate the nature of the microwave emission of 3C 396. Results show a spectral energy distribution dominated by a single component power law emission with $\alpha=(-0.364 \pm 0.017)$. Data do not favour the presence of anomalous microwave emission coming from the source. Polarised emission at 21.5 GHz is consistent with synchrotron-dominated emission. We present microwave maps and correlate them with infrared (IR) maps in order to characterise the interplay between thermal dust and microwave emission. IR vs. microwave TT plots reveal poor correlation between mid-infrared and microwave emission from the core of the source. On the other hand, a correlation is detected in the tail emission of the outer shell of 3C 396, which could be ascribed to Galactic contamination.Comment: published in MNRA

Platinum(II) and Palladium(II) Complexes of Pyridine-2-Carbaldehyde Thiosemicarbazone as Alternative Antiherpes Simplex Virus Agents

The cytotoxicity and the antivirus activity of Pd(II) and Pt(II) complexes with pyridine-2-carbaldehyde thiosemicarbazone (HFoTsc) against HSV replication were evaluated on four HSV strains—two wt strains Victoria (HSV-1) and BJA (HSV-2) and two ACVR mutants with different tk gene mutations R-100 (TKA, HSV-1) and PU (TKN, HSV-2). The experiments were performed on continuous MDBK cells and four HSV 1 and HSV 2 strains were used, two sensitive to acyclovir and two resistant mutants. The five complexes of HFoTsc, [Pt(FoTsc)Cl], [Pt(FoTsc)(H2FoTsc)]Cl2, [Pt(FoTsc)2], [Pd(FoTsc)(H2FoTsc)]Cl2, and [Pd(FoTsc)2], were found to be effective inhibitors of HSV replication. The most promising, active, and selective anti-HSV agent was found to be complex [Pt(FoTsc)(H2FoTsc)]Cl2. This complex could be useful in the treatment of HSV infections, since it is resistant to ACV mutants. PCR study of immediate early 300 bp ReIV Us1 region reveals that the complex [Pt(FoTsc)(H2FoTsc)]Cl2 specifically suppressed wt HSV-1 genome 2 hours after the infection, not inducing apoptosis/necrosis on the 8 hours after virus infection. The target was found to be most probably the viral, instead of the host cell DNA