Synthesis and Biological Activity of 2-Aryl-4-hydroxy-4-methyl-6-oxocyclohexane-1,3-dicarboxamides

Russian Journal of General Chemistry - The reaction of unsubstituted acetoacetamide with aromatic aldehydes in ethanol in the presence of piperidine gave...     

Relative Kinetic Stability of Cerium(IV) Complexes with Some Organic Compounds of the Aliphatic Series

A quantitative criterion of the kinetic stabilization of unstable metal oxidation states during complexation has been proposed on the basis of the of a comparative analysis of the stability constants β1yn and rate constants kn = 1 of intramolecular redox decomposition of cerium(IV) complexes [CeHyLn]4+y–nk with a number of aliphatic organic compounds (L = HkR, R(OH)k) in sulfate and nitrate media, as well as established correlations between log kn = 1 and log β1yn. This criterion is defined as the relative kinetic stability of the complexes to intramolecular redox decomposition –log (kn = 1/k0n = 1) determined from the log kn = 1–log β1yn correlations. The latter have been found to associeted with the Nernst equation.     

Dynamic and buckling analysis of polymer hybrid composite beam with variable thickness

This work deals with a study of the dynamic and buckling analysis of polymer hybrid composite(PHC) beam. The beam has variable thickness and is reinforced by carbon nanotubes(CNTs) and nanoclay(NC) simultaneously. The governing equations are derived based on the first shear deformation theory(FSDT). A three-phase HalpinTsai approach is used to predict the mechanical properties of the PHC. We focus our attention on the effect of the simultaneous addition of NC and CNT on the vibration and buckling analysis of the PHC beam with variable thickness. Also a comparison study is done on the sensation of three impressive parameters including CNT, NC weight fractions, and the shape factor of fillers on the mechanical properties of PHC beams,as well as fundamental frequencies of free vibrations and critical buckling load. The results show that the increase of shape factor value, NC, and CNT weight fractions leads to considerable reinforcement in mechanical properties as well as increase of the dimensionless fundamental frequency and buckling load. The variation of CNT weight fraction on elastic modulus is more sensitive rather than shear modulus but the effect of NC weight fraction on elastic and shear moduli is fairly the same. The shape factor values more than the medium level do not affect the mechanical properties.     

More efficient time integration for Fourier pseudospectral DNS of incompressible turbulence

Time integration of Fourier pseudospectral DNS is usually performed using the classical fourth-order accurate Runge-Kutta method or other second- or third-order methods, with a fixed step size. We investigate the use of higher-order Runge-Kutta pairs and automatic step size control based on local error estimation. We find that the fifth-order accurate Runge-Kutta pair of Bogacki and Shampine gives much greater accuracy at a significantly reduced computational cost. Specifically, we demonstrate speedups of 2× to 10× for the same accuracy. Numerical tests (including the Taylor-Green vortex, Rayleigh-Taylor instability, and homogeneous isotropic turbulence) confirm the reliability and efficiency of the method. We also show that adaptive time stepping provides a significant computational advantage for some problems (like the development of a Rayleigh-Taylor instability) without compromising accuracy.     

Dynamics of loop soliton solutions of $${\pmb {\mathcal {PT}}}$$PT-symmetric nonlocal short pulse equation

Nonlinear Dynamics - In this article, we present a system of coupled short pulse equations as integrability condition of associated generalized linear eigenvalue problem. We obtain system of...     

Effect of Parameters of Pulse Electrolysis on Electrodeposition of Copper–Tin Alloy from Sulfate Electrolyte

Russian Journal of Electrochemistry - The effect of pulsed electrolysis on the electrodeposition of Cu–Sn alloy from the sulfate–sulfuric acid electrolyte is studied. It is shown that...     

Reactions of 4-Propargylsulfanylquinazoline with Bromine and Iodine

Russian Journal of General Chemistry - Cyclization of 4-propargylsulfanylquinazoline under the action of iodine gave 3-iodomethyl[1,3]thiazolo[3,2-c]-quinazolinium triiodide, which is reduced with...     

Photocatalytic Systems Based on Acridine Salts Derivatives

Russian Journal of General Chemistry - The possibility of 10-methyl-9-phenylacridine iodide usage as a photocatalyst in the process of molecular hydrogen evolution in various aprotic solvents has...     

Spontaneous Surface Convection and Extraction (Stripping) Rate in Systems with Tributyl Phosphate and Di(2-ethylhexyl) Hydrogen Phosphate

Russian Journal of Applied Chemistry - Extraction of rare earth elements with solutions of di(2-ethylhexyl) hydrogen phosphate or tributyl phosphate in heptane, toluene, or tetrachloromethane is...     

Newtonian plane Couette flow with dynamic wall slip

Meccanica - The occurrence of slip complicates the estimation of the viscosity in rheometric flows. Thus, special analyses and experimental protocols are needed in order to obtain reliable...