Sulfate attack on alkali-activated slag concrete

This paper presents an investigation into durability of alkali-activated slag (AAS) concrete in sulfate environment. Two tests were used to determine resistance of AAS concrete to sulfate attack. These tests involved immersion in 5% magnesium sulfate and 5% sodium sulfate solutions. The main parameters studied were evolution of compressive strength, products of degradation, and microstructural changes. After 12 months of exposure to the sodium sulfate solution, the strength decrease was up to 17% for AAS concrete and up to 25% for ordinary Portland cement (OPC) concrete. After the same period of exposure to the magnesium sulfate solution, the compressive strength decrease was more substantial, up to 37% for OPC and 23% for AAS. The main products of degradation were ettringite and gypsum in the case of Portland cement and gypsum in AAS. OPC samples had significant expansion, cracking, and loss of concrete, while AAS samples were not expanded but cracked in the test. During experiments with the sodium sulfate solution, some increase in strength of AAS concrete was recorded, likely due to continuing hydration.     

Influence of phonon focusing on the Knudsen flow of phonon gas in single-crystal nanofilms of spintronic materials

Influence of the anisotropy of elastic energy on the phonon transport has been investigated in single- crystal nanofilms of Fe, Cu, MgO, InSb, and GaAs materials used for spintronic instruments and devices in the Knudsen flow regime of phonon gas. The dependences of the lattice thermal conductivity and lengths of free paths of phonons for all acoustic modes on the geometric parameters of the films have been considered for low temperatures with the dominance of the diffuse scattering of phonons at the boundaries. Physical aspects of the propagation of phonon modes in the films have been analyzed. It has been shown that the anisotropy of phonon transport in single-crystal films is due to the features of the propagation of phonon modes in elastically anisotropic films with a different relationship of the geometric parameters. The directions of heat flow and orientations of the film planes that yield the maximum and minimum thermal conductivity of phonons in film planes have been determined.     

Optimizing the diamond machining of ceramics on the basis of systemic analysis using neural networks

A generalized algorithm is presented for estimating the efficiency of diamond machining of ceramics. The algorithm is based on systematic analysis of the influence of the technological media and the conditions and employs up-to-date computational techniques.     

Normalizing of Vibrations in Fiberoptics Drawing Plants

The effect of vibrations of drawing plants on a deviation in the diameter of the fiber drawn is estimated. An elastic filament is accepted as a calculation model. The boundary conditions include kinematic disturbance caused by vibrations of the drawing mechanism.     

Analysis of industrial vibrations in a light guide thread drawn from a glass melt

An analysis of industrial vibrations in a light guide thread drawn from a glass melt is given within a model for a string moving at a constant velocity.Translated from Steklo i Keramika, No. 12, pp. 3–4, December, 1996     

Caustic Pattern of Magnetoelastic Waves in the Vicinity of Magnetoelastic Resonance in Fe $$_{1-x}$$ 1 - x Ga $$_{x}$$ x Crystal

Journal of Superconductivity and Novel Magnetism - The vicinities of two resonance points where longitudinal and transverse elastic waves interact with the magnetic mode are considered. The caustic...     

Heat and Particle Transport in the Initial Phase of Ohmic Discharges in the Globus-M Spherical Tokamak

Technical Physics Letters - The results of experiments and simulations of the transport of heat and particles in the Globus-M spherical tokamak are presented. Investigations were carried out in the...     

Comparative Analysis of Methods for Drawing Glass Filaments

Mechanisms for drawing glass filaments used in the optical industry are considered. The drawing mechanisms are classified according to the type of transmission used to convert the rotary motion of the drive into the translational motion of filament drawn. The main reasons for nonuniform drawing velocities and deterioration of the quality of filaments are identified.