Revealing per-grain and neighbourhood stress interactions of a deforming ferritic steel via three-dimensional X-ray diffraction

The structural performance of polycrystalline alloys is strongly controlled by the characteristics of individual grains and their interactions, motivating this study to understand the dynamic micromechanical response within the microstructure. Here, a high ductility single-phase ferritic steel during uniaxial deformation is explored using three-dimensional X-ray diffraction. Grains well aligned for dislocation slip are shown to possess a wide intergranular stress range, controlled by per-grain dependent hardening activity. Contrariwise, grains orientated poorly for slip have a narrow stress range. A grain neighbourhood effect is observed of statistical significance: the Schmid factor of serial adjoining grains influences the stress state of a grain of interest, whereas parallel neighbours are less influential. This phenomenon is strongest at low plastic strains, with the effect diminishing as grains rotate during plasticity to eliminate any orientation dependent load shedding. The ability of the ferrite to eliminate such neighbourhood interactions is considered key to the high ductility possessed by these materials

Revealing per-grain and neighbourhood stress interactions of a deforming ferritic steel via three-dimensional X-ray diffraction

The structural performance of polycrystalline alloys is strongly controlled by the characteristics of individual grains and their interactions, motivating this study to understand the dynamic micromechanical response within the microstructure. Here, a high ductility single-phase ferritic steel during uniaxial deformation is explored using three-dimensional X-ray diffraction. Grains well aligned for dislocation slip are shown to possess a wide intergranular stress range, controlled by per-grain dependent hardening activity. Contrariwise, grains orientated poorly for slip have a narrow stress range. A grain neighbourhood effect is observed of statistical significance: the Schmid factor of serial adjoining grains influences the stress state of a grain of interest, whereas parallel neighbours are less influential. This phenomenon is strongest at low plastic strains, with the effect diminishing as grains rotate during plasticity to eliminate any orientation dependent load shedding. The ability of the ferrite to eliminate such neighbourhood interactions is considered key to the high ductility possessed by these materials

Norine, the knowledgebase dedicated to nonribosomal peptides, is now open to crowdsourcing

International audienceSince its creation in 2006, Norine remains the unique knowledgebase dedicated to non-ribosomal pep-tides (NRPs). These secondary metabolites, produced by bacteria and fungi, harbor diverse interesting biological activities (such as antibiotic, anti-tumor, siderophore or surfactant) directly related to the diversity of their structures. The Norine team goal is to collect the NRPs and provide tools to analyze them efficiently. We have developed a user-friendly interface and dedicated tools to provide a complete bioinformatics platform. The knowledgebase gathers abundant and valuable annotations on more than 1100 NRPs. To increase the quantity of described NRPs and improve the quality of associated annotations , we are now opening Norine to crowdsourc-ing. We believe that contributors from the scientific community are the best experts to annotate the NRPs they work on. We have developed MyNorine to facilitate the submission of new NRPs or modifications of stored ones. This article presents MyNorine and other novelties of Norine interface released since the first publication. Norine is freely accessible from the following URL: http://bioinfo.lifl.fr/NRP

2-[2-Benzoyl-3,3-bis­(methyl­sulfan­yl)prop-2-enyl­idene]malononitrile

The title compound, C15H12N2OS2, is an example of a push–pull butadiene in which the electron-releasing methyl­sulfanyl groups and electron-withdrawing nitrile groups on either end of the butadiene chain enhance the conjugation in the system. Short intra­molecular C—H⋯S inter­actions are observed. In the crystal structure, an O⋯C short contact of 2.917 (3) Å is observed

Short range order and topology of binary Ge-S glasses

Short range order and topology of GexS100-x glasses over a broad composition range (20 ≤ x ≤ 42 in at%) was investigated by neutron diffraction, X-ray diffraction, and Ge K-edge extended X-ray absorption fine structure (EXAFS) measurements. The experimental data sets were fitted simultaneously in the framework of the reverse Monte Carlo simulation method. It was found that both constituents (Ge and S) satisfy the Mott-rule in all investigated glasses: Ge and S atoms have 4 and 2 neighbours, respectively. The structure of these glasses can be described with the chemically ordered network model: Ge-S bonds are preferred; S-S bonds are present only in S-rich glasses. Dedicated simulations showed that Ge-Ge bonds are necessary in Ge-rich glasses. Connections between Ge atoms (such as edge-sharing GeS4/2 tetrahedra) in stoichiometric and S-rich glasses were analysed. The frequency of primitive rings was also calculated

Time-resolved in-situ X-ray diffraction study of CaO and CaO:Ca3Al2O6 composite catalysts for biodiesel production

The authors would like to acknowledge Innovate UK (Project Nos. 103498 and 106037) and EPSRC (EP/K015540/1 and EP/P007821/1) for funding. This work was carried out with the support of the Diamond Light Source, instrument I12 (proposal EE20820).Alternative and sustainable waste sources are receiving increasing attention as they can be used to produce biofuels with a low carbon footprint. Waste fish oil is one such example and can be considered an abundant and sustainable waste source to produce biodiesel. Ultimately this could lead to fishing communities having their own "off-grid" source of fuel for boats and vehicles. At the industrial level biodiesel is currently produced by homogeneous catalysis because of the high catalyst activity and selectivity. In contrast, heterogeneous catalysis offers several advantages such as improved reusability, reduced waste and lower processing costs. Here we investigate the phase evolution of two heterogeneous catalysts, CaO and a Ca3Al2O6:CaO ('C3A:CaO') composite, under in-situ conditions for biodiesel production from fish oil. A new reactor was designed to monitor the evolution of the crystalline catalyst during the reaction using synchrotron powder X-ray diffraction (PXRD). The amount of calcium diglyceroxide (CaDG) began to increase rapidly after approximately 30 minutes, for both catalysts. This rapid increase in CaDG could be linked to ex-situ NMR studies which showed that the conversion of fish oil to biodiesel rapidly increased after 30 minutes. The key to the difference in activity of the two catalysts appears to be that the Ca3Al2O6:CaO composite maintains a high rate of calcium diglyceroxide formation for longer than CaO, although the initial formation rates and reaction kinetics are similar. Overall this specialised in-situ set-up has been shown to be suitable to monitor the phase evolution of heterogeneous crystalline catalysts during the triglycerides transesterification reaction, offering the opportunity to correlate the crystalline phases to activity, deactivation and stability.Publisher PDFPeer reviewe

Biological Effects of Stellar Collapse Neutrinos

Massive stars in their final stages of collapse radiate most of their binding energy in the form of MeV neutrinos. The recoil atoms that they produce in elastic scattering off nuclei in organic tissue create radiation damage which is highly effective in the production of irreparable DNA harm, leading to cellular mutation, neoplasia and oncogenesis. Using a conventional model of the galaxy and of the collapse mechanism, the periodicity of nearby stellar collapses and the radiation dose are calculated. The possible contribution of this process to the paleontological record of mass extinctions is examined.Comment: gzipped PostScript (filename.ps.Z), 12 pages. Final version, Phys. Rev. Lett., in pres

Shape modeling technique KOALA validated by ESA Rosetta at (21) Lutetia

We present a comparison of our results from ground-based observations of asteroid (21) Lutetia with imaging data acquired during the flyby of the asteroid by the ESA Rosetta mission. This flyby provided a unique opportunity to evaluate and calibrate our method of determination of size, 3-D shape, and spin of an asteroid from ground-based observations. We present our 3-D shape-modeling technique KOALA which is based on multi-dataset inversion. We compare the results we obtained with KOALA, prior to the flyby, on asteroid (21) Lutetia with the high-spatial resolution images of the asteroid taken with the OSIRIS camera on-board the ESA Rosetta spacecraft, during its encounter with Lutetia. The spin axis determined with KOALA was found to be accurate to within two degrees, while the KOALA diameter determinations were within 2% of the Rosetta-derived values. The 3-D shape of the KOALA model is also confirmed by the spectacular visual agreement between both 3-D shape models (KOALA pre- and OSIRIS post-flyby). We found a typical deviation of only 2 km at local scales between the profiles from KOALA predictions and OSIRIS images, resulting in a volume uncertainty provided by KOALA better than 10%. Radiometric techniques for the interpretation of thermal infrared data also benefit greatly from the KOALA shape model: the absolute size and geometric albedo can be derived with high accuracy, and thermal properties, for example the thermal inertia, can be determined unambiguously. We consider this to be a validation of the KOALA method. Because space exploration will remain limited to only a few objects, KOALA stands as a powerful technique to study a much larger set of small bodies using Earth-based observations.Comment: 15 pages, 8 figures, 2 tables, accepted for publication in P&S

Design and Bolometer Characterization of the SPT-3G First-year Focal Plane

During the austral summer of 2016-17, the third-generation camera, SPT-3G, was installed on the South Pole Telescope, increasing the detector count in the focal plane by an order of magnitude relative to the previous generation. Designed to map the polarization of the cosmic microwave background, SPT-3G contains ten 6-in-hexagonal modules of detectors, each with 269 trichroic and dual-polarization pixels, read out using 68x frequency-domain multiplexing. Here we discuss design, assembly, and layout of the modules, as well as early performance characterization of the first-year array, including yield and detector properties.Comment: Conference proceeding for Low Temperature Detectors 2017. Accepted for publication: 27 August 201