Electro-elastic interactions and second order anisotropic constitutive equations

Piezoelectricity is usually expressed as an interaction between mechanical and electrical variables. The physics involved is hence governed by a coupling between Maxwell's equations of electromagnetism and the equations of elasticity. Such a coupling takes us through the piezoelectric constitutive relations. In this work, the second order anisotropic constitutive equations are treated, and in particular, the number of independent material constants is computed for all the 32 crystallographic classes.Paper presented, in reduced version, at the 12th Italian National Congress of Theoretical and Applied Mechanics (AIMETA '95), October 1995, Naples, Italy.     

Estimating the plastic strain with the use of acoustic anisotropy

Experimental verification is used to show that reference specimens and structure unloading do not permit obtaining an adequate estimate of plastic strain by measuring the acoustic anisotropy. Analytic estimates of the speed of propagation of a plane acoustic wave of various polarizations in an elastoplastic material in the direction orthogonal to the action of preliminary uniaxial stress are obtained. An analysis of the obtained relations reveala an advantage of using absolute values of the velocity of longitudinal and transverse waves for the plastic strain identification. In contrast to acoustic anisotropy, the velocities vary monotonically in a wider range of plastic strains. At the same time, the elastic strain does not affect the longitude wave velocity, which allows one to use the measurement results to estimate the character of strains.     

Thermocyclic testing of heat-resistant coatings at megawatt three-phase plasmatron

Some new types of heat-resistant coatings developed at present were tested for thermal fluxes and temperatures implemented in flame channels of modern rocket engines. The megawatt three-phase alternatingcurrent plasmatron was used for testing. The thermal flux distributions were measured for uncooled targets using thermocouples and thermal imaging tools. Coated samples were installed to the model cooled by water under high pressure. The mechanical strength of coatings at thermocyclic testing was studied and heat conduction of heat-resistant layers was determined in operation conditions.     

Symmetric disjunctive list-decoding codes

In this work, we consider symmetric disjunctive list-decoding (SLD) codes, which are a class of binary codes based on a symmetric disjunctive sum (SDS) of binary symbols. By definition, the SDS takes values from the ternary alphabet \(\{0, 1, *\}\), where the symbol \(*\) denotes “erasure”. Namely: SDS is equal to 0 (1) if all its binary symbols are equal to 0 (1), otherwise SDS is equal to \(*\). The main purpose of this work is to obtain bounds on the rate of these codes.     

Design,synthesis of novel quinazolin-4-one derivatives and biological evaluation against human MCF-7 breast cancer cell line

A new series of 6,8-dibromo-2-(4-chlorophenyl)quinazolin-4(3H)-one derivatives VI–XIII were synthesized. Their chemical structures were confirmed by spectral and elemental analysis. The cytotoxic effect of the newly synthesized compounds was tested in vitro against human breast cancer cell line (MCF-7). Most of the tested compounds have shown promising cytotoxic activity. Compounds X and XIIIb exerted a powerful cytotoxic effect against MCF-7 with a very low IC50 (0.0015 and 0.0047 µmol/ml), while compounds VI, VII, VIII, XIIb, XI, XIIIc and IX exerted a moderate cytotoxic effect (IC50 0.01523, 0.0213, 0.031, 0.0478, 0.049, 0.068 and 0.079 µmol/ml respectively), compared to doxorubicin (0.0025 µmol/ml). Exploring their apoptotic effect; interestingly,all compounds activated apoptotic cascade in MCF-7. Compounds VI, XIIIb, XIIb, XI, XIIa, VII, V and VIII showed potent effect even much more than doxorubicin by 12.87–5.91 folds, while compounds XIIIc, IX, XIIIa, XIIc and X showed moderate increase in CASP3 activity by 4.96–3.22 folds relative to untreated cells more or less similar to doxorubicin (5.57 folds).     

Influence of the choice of a rheological law on computer simulation results of slab subduction

The influence of the choice of the type of yield surface for elastoplastic materials and material constants for the slab and the mantle on the scenario of mathematical modeling of the slab collision is investigated. Computer simulation is performed by the FEM numerical solution of nonlinear equations for deformable solid mechanics, using the MSC.Marc 2005 code. The simulation results essentially depend on the choice of material constants for the slab and the mantle, as well as on the type of the yield surface for the elastoplastic material of the subduction slab. The numerical simulations demonstrate that the primary driving mechanism of subduction can be a geometrical inhomogeneity of the subduction slab near the zone of the slab collision with simultaneous consideration of consolidation of the slabmaterial as the slab descends into the mantle.