Tomsk Polytechnic University

About: Tomsk Polytechnic University is a education organization based out in Tomsk, Russia. It is known for research contribution in the topics: Combustion & Ignition system. The organization has 9190 authors who have published 13224 publications receiving 103735 citations.

Heavy-to-light semileptonic decays of Λ b and Λ c baryons in the covariant confined quark model

Abstract: We present a detailed analysis of the heavy-to-light semileptonic decays of theb andc baryons �b → pl ¯ νl andc → nl + νl in the covariant confined quark model. We calculate the invariant and helicity amplitudes of the two processes which are then used to analyze their angular decay distributions, their rates and asymmetry parameters.

Effect of the Passivating Coating Type, Particle Size, and Storage Time on Oxidation and Nitridation of Aluminum Powders

Abstract: Processes of nonisothermal oxidation, nitridation, and ageing of aluminum powders with different particle sizes (nano-sized powder, ASD-1 powder, and PAP-2 powder) are considered. Application of non-oxide coatings onto particles of aluminum nanopowders reduces their thermal stability. Owing to scale-shaped particles, the PAP-2 powder after long-time storage preserves high activity of oxidation and nitridation, which is commensurable with that of the aluminum nanopowder. The activity of the coarse ASD-1 powder consisting of spherical particles in terms of oxidation and nitridation is low and only slightly changes during ageing.

Gold nanoparticles supported on magnesium oxide for CO oxidation

Abstract: Au was loaded (1 wt%) on a commercial MgO support by three different methods: double impregnation, liquid-phase reductive deposition and ultrasonication. Samples were characterised by adsorption of N2 at -96°C, temperature-programmed reduction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Upon loading with Au, MgO changed into Mg(OH)2 (the hydroxide was most likely formed by reaction with water, in which the gold precursor was dissolved). The size range for gold nanoparticles was 2-12 nm for the DIM method and 3-15 nm for LPRD and US. The average size of gold particles was 5.4 nm for DIM and larger than 6.5 for the other methods. CO oxidation was used as a test reaction to compare the catalytic activity. The best results were obtained with the DIM method, followed by LPRD and US. This can be explained in terms of the nanoparticle size, well known to determine the catalytic activity of gold catalysts.