Stress corrosion in pipes of different diameters during the nondestructive testing of gas mains

An analysis of the results of the diagnostics of the pipe state in gas mains was performed based on the data of intrapipe magnetic nondestructive testing of gas mains in order to evaluate the danger of the detected flaws and verify the accomplishment of a regular (3–5 year) intrapipe inspection.     

Friction and wear of fuel assemblies in water-moderated reactors

Static and dynamic processes that involve frictional forces are experimentally studied. The frictional forces affect the stress of the fuel assembly in all stages of the life cycle.     

J-integral evaluation for U- and V-blunt notches under Mode I loading and materials obeying a power hardening law

The paper deals with calculations of the J-integral for a plate weakened by U- and V-blunt notches under mode I loading in the case of a linear and nonlinear elastic material. The main aim of the study is to suggest simple equations suitable for rapid calculations of the J-integral. The semicircular arc of the notch, which is traction free, is assumed as integration path and the J-integral is given as a function of the strain energy over the notch edge. For a numerical investigation of the strain energy density distribution on the notch edge the equation W(θ)=W_max cos^δ(θ) has been assumed, where δ has been determined from finite element analyses. In particular, the following values of the notch acuity a/ρ and the opening angle 2α have been analyzed: 4 ≤ a/ρ ≤ 400 and 0 ≤ 2α ≤ 3π /4. Considering plates weakened by lateral and central notches under symmetric mode I loading, the approximate relationships for the strain energy density, which require the presence of a non zero notch radius for their application, and the J-integral are discussed firstly considering a linear elastic material and then a material obeying a power hardening law during the loading phase. The predicted results of the J-integral are consistent with those directly obtained from finite element analyses.     

Planar multilayer membranes on metallic supports

We have tested a number of approaches to producing oxygen-selective planar multilayer membranes with mixed conductivity of functional layers on metallic gauze as a key component of a porous support. The results demonstrate that the shrinkage mismatch can be considerably reduced via pressure sintering. The conditions for firing metallic gauzes and applying ceramic coatings have been established. We describe the optimal structure and processes for applying ceramic layers with the aim of producing planar multilayer membranes of catalytic membrane reactors for methane conversion. Mechanochemical ceramic processing was successfully used to produce ceramic nanopowders and modifying paste.     

Characterization of spinel and magnetospheres of coal fly ashes collected in power plants in the former USSR

Six samples of magnetospheres, recovered by magnetic separation from fly ashes, collected from power plants with high temperature boilers in the former USSR, were investigated by combination of instrumental techniques. The phase and chemical compositions, morphology and microstructure of magnetospheres have been studied by optical microscopy, scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM/EDX), X-ray diffraction (XRD), Mössbauer spectroscopy. Iron in magnetospheres mainly occurs as Fe-spinels, hematite, and iron bearing glass. Structural formulas of spinels promising for catalysis applications were calculated on the base of obtained results. The magnetospheres have been characterized mainly as core-shell nanocomposites from spinel, hematite and quartz crystals in glass matrix divided in high-silica and high-ferrous glasses. The mechanism of magnetospheres formation was proposed.