The effects of transition metal dopants on the catalytic properties of magnesia-supported terbium oxide catalysts in the oxidative coupling of methane were investigated. A few transition metals were included based on their oxidation states relative to Tb in TbO1.81 (where Tb is between Tb3+ and ...

We have synthesized Sm2O3 nanoparticles (SmNs) and anchored them onto the surface of reduced graphene oxide (RGO) through a self-assembly thereof by utilizing a facile sonochemical procedure. The nanomaterials were characterized by means of powder X-ray diffraction (XRD), Field-emission scanning...

A series of iron-samarium mixed oxide catalysts modified by zirconium, cobalt and titanium were prepared by co-precipitation method, and the effects of modified transition metal species and calcination temperature in preparation process on NH3-SCR activity were investigated. The catalysts were c...

Hafnium oxide nanoparticles doped with trivalent samarium (HfO2:Sm3+) were synthesized by hydrothermal route from chloride reagents. Different samarium doping concentrations (0, 0.5, 1, 3, 5 and 10 at% with respect to Hf) and different post-annealing temperatures (200, 400, 600, 800 and 1000 °C...

The effect of the addition of samarium oxide (Sm2O3) in the thermal behavior of (66%) kaolinitic ball clay was studied and compared with the pure clay.The incorporation of Sm2O3 is of technological interest for the design of smart traceable ceramic proppants used for unconventional gas and oil w...

Thin films of pristine and platinum-doped tungsten oxide were examined as potential catalysts for efficient partial oxidation of methanol. The tungsten oxide layers with different thicknesses were deposited by the means of reactive magnetron sputtering on oxidized silicon wafer and silicon coate...

Neptunium dioxide and tetrafluoride are converted in essentially quantitative yield to volatile neptunium hexafluoride by dioxygen difluoride (O2F2), both in gas–solid reactions at ambient temperatures and in liquid anhydrous hydrogen fluoride at −78°C. Neptunium dioxydifluoride was identified...

We report for the first time the thermal expansion of NpO2 up to 2000 K and compare it to the one of UO2 and PuO2. Lattice parameters were measured as a function of temperature by in situ X-ray diffraction with neutral, reducing and oxidizing atmospheres. Data for NpO2 under neutral and reducing...

The effect of Np incorporation in a UO2 matrix on redox state of U and Np cations has been investigated by X-ray absorption spectroscopy (XAS) on three samples: (U0.9Np0.1)O2, (U0.9Np0.1)O2 + x and pure NpO2, the latter of which was used as a reference for Np(IV) oxidation state. XANES at the Ur...

Neptunium, Np(V) and Np(IV), sorption onto uranium dioxide surface was studied at various values of pH. Sorption was studied in two sets of experiments with different redox conditions that correspond to either Np(V) (Set 1) or Np(IV) (Set 2) in solution. In Set 1 the reduction of Np(V) was estab...

Detailed information on neptunium(V) speciation on montmorillonite and corundum surfaces was obtained by batch sorption and desorption studies combined with surface complexation modelling using the Diffuse Double-Layer (DDL) model, in situ time-resolved Attenuated Total Reflection Fourier-Transf...

Knudsen effusion mass spectrometry measurements on neptunium dioxide are reported in this work, which have allowed to improve the understanding of its vapourization behaviour and solved discrepancies noticed in the literature: the enthalpy of formation of NpO2(g) has been re-assessed and the com...

In the present study neptunium(V) uptake by crystalline granitic rock (Kuru Grey granite) and the role of stable and mobile bentonite colloids (MX-80) on the migration of neptunium(V) was investigated. Two different experimental setups were utilized, batch-type experiments under stagnant conditi...

The molecular dynamics (MD) calculation has been performed for neptunium dioxide (NpO2) in the temperature range from 300 to 2500 K to evaluate the thermophysical properties viz., the lattice parameter, thermal expansion coefficient, compressibility, heat capacity, and thermal conductivity. The ...

The thermal diffusivity of neptunium dioxide was measured in the temperature range from 473 to 1473 K by using a laser flash method. The thermal diffusivity slightly decreased with increasing temperature in the temperature range investigated. The heat capacity of NpO2 was measured in the tempera...

Knudsen cell high temperature mass spectrometric measurements have been performed on neptunium dioxide. Several samples have been analysed for vaporisation in vacuum and oxidative conditions and different behaviours have been observed. The results for the vapour pressure of pure neptunium dioxid...

A particular palladium sulphide phase (Pd4S) supported on carbon nanofibers is shown to be one of the most selective alkyne hydrogenation catalysts reported to date. Propyne and ethyne (in the absence of the corresponding alkene) can be converted in the gas phase to the corresponding alkene with...

A recent trend for application of shape memory alloys is concerned with the development of micro- and nano-scale devices where increasingly more precise effects caused by reversible martensitic transformations are taken into consideration or used. As a result, effects finer than one-way shape me...

The size and morphology of Ti3Ni4 precipitates, as well as their transformation behavior after isothermal aging, were studied in a Ti-50.7 аt.%Ni shape memory alloy with various B2 austenite grain sizes. A 0.3 mm thick band with an accumulated strain of ε = 44% (e = 0.6) obtained by cold rolli...

It is shown that in alloys with thermoelastic martensitic transformations, shape memory and superelasticity effects, the real yield stress (τ0.3) can be determined only by a joint analysis of “stress-total strain” and “plastic deformation-total strain” dependences. We suggest to determine o...