Thermal Treatments of AlSi10Mg Processed by Laser Beam Melting

Recent studies have shown that AlSi10Mg processed by Laser Beam Melting (LBM) exhibits a much finer microstructure when compared to its cast counterpart as a consequence of the much faster cooling rates imposed in the LBM process. Such microstructural refinement causes a significant increase in strength and hardness, to such an extent that as-fabricated LBM AlSi10Mg was reported to present hardness value of 127 ± 3 Hv0.5, similar to the hardness of high pressure die cast AlSi10Mg in the aged condition (i.e. 130-133 Hv). Yet, little attention has been given so far to the influence of thermal treatments on the microstructure and mechanical behavior of LBM AlSi10Mg. The present work hence aims to investigate the effect of two different types of heat treatments – i.e. (i) stress relief and (ii) solutionizing and ageing − on the microstructure, hardness and tensile properties of LBM AlSi10Mg.Mechanical Engineerin

Side-channel based intrusion detection for industrial control systems

Industrial Control Systems are under increased scrutiny. Their security is historically sub-par, and although measures are being taken by the manufacturers to remedy this, the large installed base of legacy systems cannot easily be updated with state-of-the-art security measures. We propose a system that uses electromagnetic side-channel measurements to detect behavioural changes of the software running on industrial control systems. To demonstrate the feasibility of this method, we show it is possible to profile and distinguish between even small changes in programs on Siemens S7-317 PLCs, using methods from cryptographic side-channel analysis.Comment: 12 pages, 7 figures. For associated code, see https://polvanaubel.com/research/em-ics/code

Bonding mechanism in the nitrides Ti2AlN and TiN: an experimental and theoretical investigation

The electronic structure of nanolaminate Ti2AlN and TiN thin films has been investigated by bulk-sensitive soft x-ray emission spectroscopy. The measured Ti L, N K, Al L1 and Al L2,3 emission spectra are compared with calculated spectra using ab initio density-functional theory including dipole transition matrix elements. Three different types of bond regions are identified; a relatively weak Ti 3d - Al 3p bonding between -1 and -2 eV below the Fermi level, and Ti 3d - N 2p and Ti 3d - N 2s bonding which are deeper in energy observed at -4.8 eV and -15 eV below the Fermi level, respectively. A strongly modified spectral shape of 3s states of Al L2,3 emission from Ti2AlN in comparison to pure Al metal is found, which reflects the Ti 3d - Al 3p hybridization observed in the Al L1 emission. The differences between the electronic and crystal structures of Ti2AlN and TiN are discussed in relation to the intercalated Al layers of the former compound and the change of the materials properties in comparison to the isostructural carbides.Comment: 18 pages, 7 figures; http://link.aps.org/doi/10.1103/PhysRevB.76.19512

AMBER on the VLTI: data processing and calibration issues

We present here the current performances of the AMBER / VLTI instrument for standard use and compare these with the offered modes of the instrument. We show that the instrument is able to reach its specified precision only for medium and high spectral resolution modes, differential observables and bright objects. For absolute observables, the current achievable accuracy is strongly limited by the vibrations of the Unit Telescopes, and also by the observing procedure which does not take into account the night-long transfer function monitoring. For low-resolution mode, the current limitation is more in the data reduction side, since several effects negligible at medium spectral resolution are not taken into account in the current pipeline. Finally, for faint objects (SNR around 1 per spectral channel), electromagnetic interferences in the VLTI interferometric laboratory with the detector electronics prevents currently to get unbiased measurements. Ideas are under study to correct in the data processing side this effect, but a hardware fix should be investigated seriously since it limits seriously the effective limiting magnitude of the instrument.Comment: 10 page

Isolation of pregnancy-associated glycoproteins (PAG) from water buffalo (Bubalus bubalis) placenta by use of Vicia villosa bound agarose affinity chromatography

The present study describes the isolation and characterisation of new PAG molecules extracted from mid- and late-pregnancy placentas in the water buffalo (Bubalis bubalis). After extraction, acid and ammonium sulphate precipitation and DEAE chromatography water buffalo PAG (wbPAG) were enriched by Vicia villosa agarose (VVA) affininity chromatography. As determined by Western blotting with anti-PAG-sera, apparent molecular masses of immunoreactive bands from VVA peaks ranged from 59.5 to 75.8 kDa and from 57.8 to 80.9 kDa in the mid- and late- pregnancy placenta respectively. Aminoterminal microsequencing of proteins allowed the identification of three distinct wbPAG sequences wich have ben deposed in the SwissProt database: RGSXLTIHPLRNIRDFFYUG (Acc. n. P85048), RGSXLTILPLRNIID (P85049) and RGSXLTHLPLRNI (P85050). Their comparison to those previously identified revealed that two of them were new since they have not been described yet. Our results confirm the suitability of VVA chromatography in enrichment of multiple PAG molecules expressed in buffalo placenta. Productions of specific antisera can be very useful in immonoistochemical and immunocyitochemical studies of PAG expression in fetomaternal interfaces. Purified native PAG are also required for development on specific immoassays (RIA/ELISA) currently used for pregnancy diagnosis and physiological investigation in farm animal