Mechanocomposites based on tungsten and interactive metals

Mechanocomposites composed of tungsten and metals interacting with it, such as nickel and iron, have been studied; a composition, structure, density, and strength of samples obtained at the stages of mechanical alloying, compacting, and sintering have been considered.     

Formation of cube texture during annealing of rolled tapes from alloys Ni95.3Mo4.7 and Ni48.8Fe51.2

The paper deals with the study of the process of the formation of the primary recrystallization texture in Ni_95.3Mo_4.7 and Ni_48.8Fe_51.2 nickel alloys during annealing after deformation by rolling to large reduction. The electron backscatter diffraction method is used to show the effect of the temperature and the heating rate during annealing on the structure and texture in alloys that differ in the temperature of the beginning of primary recristallization. The majority of attention is focused on investigating the possibility of estimating the temperature range of primary recrystallization from the dilatometry anomaly on the temperature dependence of the thermal expansion coefficient. Variations in the relief of the rolled tapes after recrystallization are studied.     

Effect of fluorinated substituents on hydrodynamic and conformational properties of hyperbranched polycarbosilane in solutions

Fractions of hyperbranched polycarbosilane modified with fluorine-containing end groups are studied by the methods of molecular hydrodynamics and optics in dilute solutions in hexafluorobenzene, methyl tert-butyl ether, chloroform, tetrahydrofurane, and toluene. The results are compared with the data available for the original polymethylallylcarbosilane. The incorporation of fluorinated groups leads to a change in the hydrodynamic parameters of the hyperbranched polymer. In this case, in thermodynamically better solvents, the patterns of the molecular-mass dependence of intrinsic viscosity for fluorinated and original hyperbranched polycarbosilanes coincide since the macromolecules of the polymers under comparison are characterized by similar shapes and almost the same hydrodynamic sizes. In a thermodynamically worse solvent (toluene), the above-mentioned changes in hydrodynamic parameters and the character of the molecular-mass dependences are related to compaction of macromolecules and a decrease in their shape asymmetry. This tendency is probably associated with the selectivity of this solvent with respect to the fluorine atom.     

Dissolution of Metal Oxides in a Choline Chloride–Sulphosalicylic Acid Deep Eutectic Solvent

Theoretical Foundations of Chemical Engineering - A choline chloride–sulfosalicylic acid deep eutectic solvent (DES) is proposed for dissolving the oxides Co(II), Cu(II), Zn(II), Fe(III),...     

Laser Writing of Crystalline Structures in Lithium-Niobium-Germanate Glasses

Glass and Ceramics - It is demonstrated that spatially selective crystallization of lithium-niobium-germanate glasses with the compositions (mol.%) 25Li2O?30Nb2O5?45GeO2 and...     

Photoluminescence of Gallate Glass-Ceramics: Al2O3 Influence

Glass and Ceramics - The influence of Al2O3 as an additive and the heat-treatment regime on the luminescence spectra of gallate glass-ceramics was investigated. It is shown that its luminescence...     

Development,construction, and use of pneumometric tubes for measurement of steam flow in the steam lines of PVG-1000 at NPP

A system for the direct measurement of steam flow in steam lines after a steam generator, which utilizes a special design of pneumometric tubes and a computing unit that accounts for variation in steam pressure, has been developed to improve the quality of water-level regulation in the steam generators of VVéR-1000 power-generating units in the stationary and transitional modes. The advantage of the pneumometric tubes consists in their structural simplicity, high erosion resistance, and absence of irrevocable losses during measurement of steam flow. A similar measurement system is used at foreign NPP. The measurement system in question has been placed in experimental service at the No. 3 unit of the Balakovo NPP, and has demonstrated its worthiness. This measurement system can also be used to determine steam flow in the steam lines of NPP units with VVéR-1000 and VVéR-440 reactors, and PBMK-1000 power-generating units. __________ Translated from élektricheskie Stantsii, No. 3, March 2007, pp. 23–26.     

Catalytic and physicochemical properties of Fe-polymer nanocatalysts of Fischer–Tropsch synthesis: Dynamic light scattering and FTIR spectroscopy study

Catalytic and structural properties of ultrafine, including nanosized, Fe-polymer catalysts of Fischer–Tropsch synthesis have been studied. The use of dynamic light scattering and ATR FTIR spectroscopy has made it possible to analyze structural features of the polymer matrix surrounding an active metal-containing nanoparticle and to relate them to catalyst activity in Fischer–Tropsch synthesis.