Liquid Structure of Magnesium Aluminates.

Magnesium aluminates (MgO)(AlO) belong to a class of refractory materials with important applications in glass and glass-ceramic technologies. Typically, these materials are fabricated from high-temperature molten phases. However, due to the difficulties in making measurements at very high temperatures, information on liquid-state structure and properties is limited.

Study of the Partial Charge Transport Properties in the Molten Alumina via Molecular Dynamics.

Knowing the charge-transport properties of molten oxides is essential for industrial applications, particularly when attempting to control the energy required to separate a metal from its ore concentrate. Nowadays, in the context of a drastic increase of computational resources, research in industrial process simulation and their optimization is gaining popularity. Such simulations require accurate data as input for properties in a wide range of compositions, temperatures, and mechanical stresses.

Does eating oily fish improve gestational and neonatal outcomes? Findings from a Sicilian study.

Background: Fish is a source of long-chain polyunsaturated n-3 fatty acids, but it may also contain a number of pollutants.

Methods: Between April and July 2013, we selected 114 women who gave birth to living babies, and divided them according to type and frequency of the fish consumed. We evaluated both gestational and neonatal outcomes.

Ion specific effects on the structure of molten AF-ZrF4 systems (A+ = Li+, Na+, and K+).

The structure of AF-ZrF(4) system (A(+) = Li(+), Na(+), K(+)) compounds in the liquid state is studied using an approach combining EXAFS spectroscopy with molecular dynamics simulations. A very good agreement is observed between the two techniques, which allows us to propose a quantitative description of the liquids. From the Zr(4+) solvation shell point of view, we observe a progressive stabilization of the 7-fold and then of the 6-fold coordinated complexes when passing from Li(+) to Na(+) and K(+) as a "counterion".

In situ experimental evidence for a nonmonotonous structural evolution with composition in the molten LiF-ZrF4 system.

We propose in this paper an original approach to study the structure of the molten LiF-ZrF(4) system up to 50 mol % ZrF(4), combining high-temperature nuclear magnetic resonance (NMR) and extended X-ray absorption fine structure (EXAFS) experiments with molecular dynamics (MD) calculations. (91)Zr high-temperature NMR experiments give an average coordination of 7 for the zirconium ion on all domains of composition. MD simulations, in agreement with EXAFS experiments at the K-edge of Zr, provide evidence for the coexistence of three different Zr-based complexes, [ZrF(6)](2-), [ZrF(7)](3-), and [ZrF(8)](4-), in the melt; the evolution of the concentration of these species upon addition of ZrF(4) is quantified.

Magnetic critical scattering in solid CoPd.

Using small-angle neutron scattering combined with a containerless aerodynamic levitation technique for high temperatures, we have measured the temperature dependence of the correlation length ξ of near-critical magnetic fluctuations in the solid phase of the completely miscible fcc alloy CoPd. A fit to our data yields a critical exponent ν = 0.76 ± 0.

Structure of molten yttrium aluminates: a neutron diffraction study.

We used the aerodynamic levitation technique combined with CO laser heating to study the structure of liquid yttrium aluminates above their melting point with neutron diffraction. For various yttria contents, we determined the structure factors and corresponding pair correlation functions describing the short-range order in the liquids. In particular, we derived Al-O and Y-O bond distances and coordination numbers.

Longitudinal excitations in Mg-Al-O refractory oxide melts studied by inelastic x-ray scattering.

The dynamic structure factor S(Q,omega) of the refractory oxide melts MgAl2O4 and MgAl4O7 is studied by inelastic x-ray scattering with aerodynamic levitation and laser heating. This technique allows the authors to measure simultaneously the elastic response and transport properties of melts under extreme temperatures. Over the wave vector Q range of 1-8 nm-1 the data can be fitted with a generalized hydrodynamic model that incorporates a slow component described by a single relaxation time and an effectively instantaneous fast component.

Structural properties of molten dilute aluminium-transition metal alloys.

The short-range order in liquid binary Al-rich alloys (Al-Fe, Al-Ti) was studied by x-ray diffraction. The measurements were performed using a novel containerless technique which combines aerodynamic levitation with inductive heating. The average structure factors, S(Q), have been determined for various temperatures and compositions in the stable liquid state.

Atomic surrounding of Co implanted in AIN at high energy.

AlN bulk ceramic has been implanted with energetic Co ions. In order to accurately characterise the atomic surrounding of the implanted ions. X-ray absorption measurements were carried out at 80 K in the fluorescence mode at the Co K edge in the as-implanted and annealed states.

Study by X-ray absorption spectroscopy of Si3N4 films after Cu or Fe implantation and thermal treatment.

Si3N4 amorphous thin layers prepared by sputtering have been implanted either with Cu or with Fe ions. X-ray absorption spectroscopy was performed at the Si K edge to characterise the electronic empty states of p character, the structural state of the initial layers and the modifications around Si induced by implantation and a post-annealing treatment. We show that the energy deposition process mainly leads to a reorganisation of the second coordination shell around Si, i.