Multifractal Parametrization of the Structure of Deformed Carbon Fibers

Deformed carbon fibers are investigated, and their failure model is proposed based on the Sierpinski set and the hypothesis of two — brittle and viscous — fracture modes, whose existence is confirmed by examples of a correlation between the mechanical strength and elastic modulus of the fibers. For the first time, a multifractal diagram is obtained, which allows one to justify the classification of carbon fibers into brittle and inelastic ones.     

Study of the microstructure and specifics of destruction of epoxide matrices

The phase structure of EDT-69N epoxide binding material is studied. It is shown that phase disintegration in a solidified epoxide polymer takes place under loading and heating and destruction upon compression, shearing, and bending occurs torsionally. It is necessary to take into account this type of matrix destruction when predicting the mechanical properties of composite materials.     

The LEPTA diagnostics and control system

The Low Energy Particle Toroidal Accumulator (LEPTA) is expected to provide experiments with intense flux of positronium. The diagnostics and control system of LEPTA consists of PCs and electronic equipment grouped in accordance with their applications. Devices in CAMAC standard, instrumentation and specially designed control cards imbedded in the LEPTA equipment are used.     

Acetaldehyde adsorption on aluminium oxide

Acetaldehyde adsorption forms were studied on -Al₂O₃ and -Al₂O₃ treated with HCl. Aldehyde was shown to produce three forms of surface compounds. At the same time partial condensation of the aldehyde was observed with the formation of unsaturated compounds. The possible participation of surface compounds in catalytic reactions of aldehydes involving aluminium oxide was also investigated.

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-Al₂O₃ -Al₂O₃, HCl. , . . Al₂O₃.

     

Optical spectra of CaF2(Tb) crystals

The luminescence and absorption spectra of fluorite crystals, alloyed with terbium fluorides, oxyfluorides, and oxides at concentrations of 0.01 to 5 mol.% were studied. The change in the optical spectra was studied as a function of the chemical composition of the alloy addition and also as a function of the concentration. It is proposed that the change with the concentration in the spectra of the crystals takes place as a consequence of mutual interactions between the ions with formation of cation pairs. It was observed that the ratio of the relative luminescence intensities of the crystals to the absorption coefficient changes nonlinearly with the concentration of the alloying addition. The problem of an interaction between an isomorphic admixture and crystal defects is discussed.In conclusion, the authors express their gratitude to E. V. Sobolev and M. V. Konovalova for help in the work.     

Capillary hydrodynamics of oligomer binders

In this work, we consider wetting and flow of oligomer binders for tissue fibers made of carbon and organic fibers. A correlation between the specific surface of fibers and strength of the boundary layers is established. The effect of fibers on structure formation of binders in the boundary layers is explained via the surface density of reticulation of fiber. The fibers with minimum surface reticulation exert a pronounced influence on the structure of binders, forming thicker and strong boundary layers.