26 research outputs found
Determination of the static modulus of elasticity of the ceramics based on zirconium dioxide
Acoustic emission during electrohydrodynamic instability development in a nematic liquid crystal
It is experimentally demonstrated that a nonstationary motion of the convective rolls in a nematic liquid crystal is accompanied by the generation of acoustic waves. Informative parameters of the acoustic emission exhibit correlations with the type, morphology, and dynamics of the dissipative structures appearing in a cell with a large aspect ratio during increase in the critical parameter. We show a principal possibility to provide a quantitative description of the chaotic dynamics of dissipative structures in the space of parameters of the observed acoustic emission. © 2001 MAIK "Nauka/Interperiodica"
Use of the hot wire method for measuring the thermal conductivity of lightweight, fiber, and powder refractory materials
Acoustic emission during a phase transition of the first kind in a liquid crystal
Crystallization with a volume contraction effect is accompanied by the radiation of sound - acoustic emission (AE). It is proposed in the theory in [2] that the sources of the ultrasonic waves are the fluctuationally occurring nuclei of the daughter phase. The integral characteristics of the AE flux generated in the phase transition are determined by the structure of the nuclei, and the thermokinetics and dynamics of their evolution. However, as a result of methodological errors in the measurement of the AE parameters and the weak dominance over noise of the latter, the available experimental data are obviously insufficient for a unique identification of the mechanisms responsible for the acoustic radiation. The present paper describes the AE which is directly correlated with the elementary processes of the formation and growth of a new phase in the crystallization of a smectic liquid crystal (LC) of cholesterylpelargeonate