Estimation of detector responses by midway forward and adjoint Monte Carlo coupling in nuclear systems

Applied Science

Advantage of Fast Fourier Interpolation for laser modeling

The abilities of new algorithm – 2D Fast Fourier Interpolation (FFI) with magnification factor (zoom) 2$^{\rm n}$ to improve the spatial resolution when necessary are analyzed in details. FFI procedure is useful when diaphragm/aperture size is less than half of current simulation scale. The computation noise due to FFI procedure is less than 10$^{-6}$. The additional time for FFI is approximately equal to one Fast Fourier Transform execution time. For some applications using of FFI procedure decreases the execution time in 10$^{4}$ times compared with other laser simulation codes

New mixed perovskite-type Gd2–xSr1+xFe2O7 catalysts for dry reforming of methane, and production of light olefins

The catalytic properties of complex perovskite-type gadolinium and strontium oxides in carbon dioxide reforming of methane and the production of gaseous olefins by carbon monoxide hydrogenation have been studied. Samples of Gd2SrFe2O7 and Gd2–xSr1+xFe2O7 (х = 0.1; 0.2; 0.3; and 0.4) have been obtained by the sol–gel method and ceramic technology, and have been characterized by means of X-ray diffraction, scanning electron microscopy, photon correlation spectroscopy, Mössbauer spectroscopy, and N2 adsorption–desorption analysis. It has been shown that the sol–gel method allows us to produce samples with better catalytic characteristics than ceramic systems. The nonisovalent substitution of Gd3+ for Sr2+ distorts the structure of complex oxide, resulting in the emergence of the heterovalent state of iron atoms (Fe3+ and Fe4+) reflected in the values of reactant conversion and selectivity for the target products. A sample of Gd2–xSr1+xFe2O7 with х = 0.3 displays the highest catalytic activity in dry reforming of methane reforming, along with the highest selectivity for unsaturated hydrocarbons (ethylene and propylene) in hydrogenation of carbon monoxide. © 2017, Pleiades Publishing, Ltd

New mixed perovskite-type Gd2–xSr1+xFe2O7 catalysts for dry reforming of methane, and production of light olefins

The catalytic properties of complex perovskite-type gadolinium and strontium oxides in carbon dioxide reforming of methane and the production of gaseous olefins by carbon monoxide hydrogenation have been studied. Samples of Gd2SrFe2O7 and Gd2–xSr1+xFe2O7 (х = 0.1; 0.2; 0.3; and 0.4) have been obtained by the sol–gel method and ceramic technology, and have been characterized by means of X-ray diffraction, scanning electron microscopy, photon correlation spectroscopy, Mössbauer spectroscopy, and N2 adsorption–desorption analysis. It has been shown that the sol–gel method allows us to produce samples with better catalytic characteristics than ceramic systems. The nonisovalent substitution of Gd3+ for Sr2+ distorts the structure of complex oxide, resulting in the emergence of the heterovalent state of iron atoms (Fe3+ and Fe4+) reflected in the values of reactant conversion and selectivity for the target products. A sample of Gd2–xSr1+xFe2O7 with х = 0.3 displays the highest catalytic activity in dry reforming of methane reforming, along with the highest selectivity for unsaturated hydrocarbons (ethylene and propylene) in hydrogenation of carbon monoxide. © 2017, Pleiades Publishing, Ltd

Catalytic hydrogenation of carbon monoxide over nanostructured perovskite-like gadolinium and strontium ferrites

The catalytic properties of perovskite-like ferrites (An + 1BnO3n + 1, where n = 1, 2, 3, …, ∞; A = Gd, Sr; and B = Fe) synthesized via ceramic and sol-gel technology in the hydrogenation of carbon monoxide are studied. The interrelation between catalytic activity, selectivity to olefins and synthetic methods for complex oxide preparation, the number of perovskite layers, crystallite size, composition, and the valence state of iron is established. © 2016, Pleiades Publishing, Ltd

Interaction between carbon oxides, hydrogen and Fe2O3 and An + 1FenO3n + 1 (A = Gd, Sr, n = 1, 2, …, ∞)

The interaction between carbon oxides and hydrogen and surfaces of iron(III) oxide and An + 1FenO3n + 1 (where A = Gd, Sr, and n = 1, 2, …, ∞ is the number of perovskite layers) complex oxides is studied for the first time by means of thermal programmed desorption. It is shown that carbon oxides are adsorbed in molecular form with the formation of carbonate–carboxylate complexes, and in dissociative form. The ratios of the adsorption forms of both oxides are determined by the structure of ferrites, the number of perovskite layers, and the valence state and coordinative saturation of iron. The presence of weakly and strongly bonded hydrogen forms is established, and it is suggested that hydrogen dissolves in the bulk of a perovskite. © 2016, Pleiades Publishing, Ltd