Mechanics

Single Waves in a Gas-Liquid Bubble Mixture

Authors: Shagapov V. S., Galimzyanov M. N., Agisheva U. O.

Nonlinear wave processes in a two-phase medium (bubbly liquid) do not lose their relevance asan object of study due to their wide use in various fields of physics, engineering, chemical and petroleum industries. Last decades the jump in the development of computing has expanded the possibilities for the study of significantly nonlinear problems. The aim of this work was to obtain a stationary solution of equations describing the motion of a solitary wave in a gas-liquid mixture without taking into account dissipative processes.

Mathematical Modeling of Deposits Accumulation on the Plastic Biliary Stent Surface for Predicting Its Occlusion

Authors: Kuchumov A. G.

Endoprosthetics with plastic stents has been used to restore bile drainage through the percutaneous or endoscopic method since the late 1970s. The long-term results cannot be considered satisfactory due to the high incidence of jaundice recurrence which is caused by the occlusion of plastic stents with a biliary sludge (accumulation of cholesterol crystals, pigment crystals, bacteria and calcium salts). Cholesterol is considered to be the main component of biliary sludge that stimulates the reduction of the stent lumen. The average lifetime of stents is 3–6 months.

Influence of Convolution Kernel and Beam-Hardening Effect on the Assessment of Trabecular Bone Mineral Density Using Quantitative Computed Tomography

Authors: Ivanov D. V., Kirillova I. V., Kossovich L. Y., Bessonov L. V., Petraikin A. V., Dol A. V., Ahmad E. S., Morozov S. P., Vladzymyrskyy A. V., Sergunova K. A., Kharlamov A. V.

Quantitative computed tomography along with densitometry is used to assess mineral density and strength of bone tissue. Raw data obtained by computed tomography are converted by software using convolution kernels. It is known that the use of convolution kernels can significantly change tissue density, which is measured in Hounsfield units. The beam-hardening effect is described in literature: when x-ray passes through an object, the absorption of lower-energy x-ray photons occurs.

Unsteady Electromagnetic Elasticity of Piezoelectrics Considering Diffusion

Authors: Zverev N. A., Zemskov A. V., Tarlakovsky D. V.

The paper considers a model of the linear theory of deformation of elastic continuum with diffusion and piezoelectric effect taken into account, which describes the relationship between mechanical deformations, mass transfer, and the internal electric field. A one-dimensional model of electromagnetic diffusion in a rectangular Cartesian coordinate system is used.