Protolytic Equilibria of Some N,N-Bis(2-carboxyethyl)aminoazobenzenesulfonic Acids in Aqueous Solution

4-[4-Bis(2-carboxyethyl)aminophenylazo]benzenesulfonic acid and 4-[2-bis(2-carboxyethyl)amino-4,5-dimethylphenylazo]benzenesulfonic acid were synthesized for the first time by azo coupling of diazosulfanilic acid with N,N-bis(2-carboxyethyl)aniline and N,N-bis(2-carboxyethyl)-3,4-xylidine, respectively. The acid ionization constants of the products were determined, their electron absorption spectra were measured, and schemes of acid-base equilibria in aqueous solution were proposed.     

Application of correlation speckle photography for measuring contact pressures

A method for measuring contact pressures based on the measurement of irreversible changes in a surface microrelief by the speckle photography technique is presented. The analytic dependence between the change in the contrast of the carrying Young’s fringes and the relative area of change in the microrelief is considered. An example of a contact interaction between a cylinder end and a flat slab, the latter with a specially produced regular roughness on its contact surface, is used to experimentally verify the relation between the irreversible change in the roughness, the change in the contrast of the holographic interference fringes, and the change in the contrast of the carrying Young’s fringes. It is shown that the sensitivity of correlation speckle photography is higher than the sensitivity of the correlation holographic interferometry technique.     

Study of the Mechanism of the Proteolytic Stage of Enzymatic Coagulation of Milk Casein

Dependence of the rate constant of the enzymatic stage of casein coagulation in milk on the concentration of casein micelles is analyzed. The dependences for a number of limiting cases that are satisfactorily consistent with published experimental data are estimated.     

Critical dynamics of slightly disordered spin systems

A new approach to the analysis of magnetic dipole motion in external magnetic field and fields generated by neighboring magnetic dipoles is suggested, and original general kinetic equations for the dipole density are derived. Special cases of these general equations are the Bloch, Redfield, and Provotorov equations, which are widely used in NMR theory. A comparison between NMR spectra calculated with the new theory and published experimental data also shows good agreement in regions to which the equations listed above do not apply. Zh. éksp. Teor. Fiz. 113, 967–980 (March 1998)     

Reduction of dimension of optimal estimation problems for dynamical systems with singular perturbations

The possibility of applying the method of integral manifolds to the reduction of optimal filtering problems for systems with low energy dissipation is explored. For such systems, it is shown that the slow subsystem of matrix Riccati differential equations turns out to have a higher dimension than expected, which leads to an increase in the dimension of the reduced problems. An optimal filter is constructed for the Langevin equation and for a dynamic model of a single-link flexible manipulator.     

Deformation and Fracture of High Entropy AlCoCrFeNi Alloy

Russian Physics Journal - Wire arc additive manufacturing in pure argon is used to fabricate the high entropy alloy system Al–Co–Cr–Fe–Ni of the nonequiatomic composition:...